I have an i386 machine with an old 8 bit 3c503 card; this card is lame
enough that it produces a handful of "ring buffer overruns" under heavy
network load.  This machine both serves and clients NFS.  Due (I presume)
to the ethernet card, access (read/write) of file larger than ~6K hangs.
(5.8K works, 6.2K fails).

This problem of hanging really sucked before I loaded the mount_nfs with
-disR5 so I can ^C out and hung calls.  

I plan to trigger the kernel debugger on this machine to determine where 
the process is hanging.  I plan to examine the nfs code to see what might
be magic about 6K.  Has anyone else seen this sort of problem or have
experience with nfs hangs/old evil ethernet cards.

-j