Ethernet controller differences between 4D/340 and 4D/25

[Vernon Schryver]

In article <9101182254.AA12177 at chem.chem.ucsd.edu>, sdempsey at UCSD.EDU (Steve Dempsey) writes:
> ....
> The Big Question:
>     What is different about the 240/340 and 25 that would account for this
>     behavior? 

They're very similar designs based on 7990's, as you no doubt noticed if
you examined the chips on the IO2 and the 4D25.

It would pay to check for errors with `netstat -i`, and for the tired old
ethernet complaints on the consoles (e.g. "late collisions" on the machines
in question or on any other IRIS on any ethernet between the ends of the
FTP transfer).  Perhaps there is some kind of grounding or other difference
that makes one of the machines unable to hear the ACK's from the remote
machine.  (E.g. the frame grounding differences among Ethernet 1, 2, and
802.3 cables and transcievers.)  I also seem to recall some differences in
the 802.3/e1/e2 transformers between the IO2 and the 4D25.  It might pay to
switch cables and transcievers.


Vernon Schryver,   vjs at sgi.com