[rescue] FDDI primer

[Dave McGuire]

On January 17, Kurt Mosiejczuk wrote:
> So, it's got me wondering... if I wanted to go to a FDDI setup, how
> would I?

  Get FDDI stuff, put it together, move data! ;)

> Do people have recommendations on stuff?
> 
> I figure things like:
> 
> What card should I look for for my:
> 	PC (PCI, ISA, PCMCIA??)?
> 	Sbus Sparc?
> 	PCI Sparc?
> 	SGI?
> 	Alpha?
> 
> What do I need?  Just a FDDI hub?  Cabling?

  First of all...FDDI has "concentrators", not hubs.  You can look at
them as being pretty much the same in the sense that you "plug a lot
of FDDI cables into them", but that's where the similarity ends.

  By far the best FDDI interfaces I've used for PCI are DEC DEFPA cards
and various cards by SysKonnect.  I don't know if DEC is still making
DEFPAs (they were as of about a year ago) but SysKonnect is making
FDDI interfaces by the truckload.  The SysKonnect boards work great
under Solaris.  The DEC boards are supported by NetBSD on pretty much
every platform that supports PCI.  Their architecture is similar to
that of their DEFTA and DEFEA boards, for TurboChannel and EISA
respectively, and are equally well-supported by NetBSD (and OpenBSD,
assuming they're copying the NetBSD sources as frequently as they used
to).  They're fast and easy to work with.  There's a DEC Qbus FDDI
interface, but they're very rare.  For bigger DEC machines, there are
XMI FDDI interfaces as well.

  There are Sbus FDDI interfaces, but they're not well documented and
as such aren't supported by any free OSs.  Geoff Adams is working on a
driver for one of those Sbus FDDI boards, but work is going slowly
because he has other responsibilities.  He's a stellar programmer
though, so I'm sure he'll get it working...it's just a matter of
time.  Many of those boards are, however, supported under SunOS4 and
Solaris.

  SGI...There are FDDI interfaces for almost all SGI machines, and
they're fairly easy to find.  Greg Douglas at Reputable had a bunch of
GIO64 FDDI interfaces for I^2 machines the last time I spoke with
him.  Interphase 4211 VME FDDI interfaces work in VME SGI machines
and are supported by IRIX.  There are GIO32 FDDI interfaces for Indy
machines.

  For Alphas...use DEFTA boards for TurboChannel machines, DEFPA
boards for PCI.  For PCI SPARC machines, get one of those SysKonnect
boards.  They have a 64-bit PCI version, and it's VERY fast.

  I've never heard of a PCMCIA FDDI interface.  Stay away from any ISA
FDDI hardware that you might find...FDDI is faster than ISA, and ISA
blows dog anyway.

  Approximate eBay pricing for some of these boards:

    DEFTA - $10
    DEFEA - $10
    DEFPA - $40
    SysKonnect 32-bit PCI: maybe $50
    SysKonnect 64-bit PCI (current boards): $60-150
    XMI FDDI: About $1000-1500
    Qbus FDDI: $800-1000

  As for concentrators...Get a Cisco WS-C1400.  They show up on eBay all
the time.  Don't pay more than $100.00 for it.  They have two
slots...make sure there the one you buy has at least one line card.
These are wonderful boxes.  They're 2U rackmount.

  FDDI cables usually use either MIC, SC, or ST connectors.  Most
newer interface cards you'll see will have SC connectors, but not
all...the rest will have MIC and still fewer will have ST.  Most
concentrators use MIC connectors.  The fiber is 62.5/125 multimode.
Don't confuse this with 50/125 fiber that's common for FC-AL stuff.
FDDI cables typically cost around $100/ea new, but can be had on eBay
for $10/ea pretty readily.  Just keep looking and they will turn up.

  To get started, you will need a concentrator and an interface card for
each machine that's supported by your OS.

  Would you like some more technical information to read about?  I can
type some more later today if you're interested.  I can tell you
basically how it works, how it's better than ethernet, the rules for
connecting things together, etc etc..

       -Dave

-- 
Dave McGuire
St. Petersburg, FL         "Less talk.  More synthohol." --Lt. Worf