Subject: 3c509 driver added.
To: None <current-users>
From: Herb Peyerl <hpeyerl>
List: current-users
Date: 12/13/1993 20:53:27
I just committed my 3Com Etherlink-III (3c509) driver that I've
been working on since the beginning of time.

The 3c509 is an icky card that more and more people are buying
and was a *real* bear to make work.  Charles and Theo helped to 
make it *haul butt*.  Between two NetBSD boxes with 3c509's in
each; I was seeing speeds of 1010KB/sec using ttcp.  

There are a few caveats:

1) There is currently no multicast support
2) There is no support for multi-3c509's in the same box.
3) I haven't tested the trailer support.
4) There have been reports of mbuf lossage during severe beatings.
   (I have been unable to reproduce this but haven't tried very hard).
5) Because of the way the card works; it is possible to underrun the transmit
   buffer.  When this happens; the driver will lose that packet and
   self-adjust to increase the threshold.  After a short period of time
   it will be optimally adjusted.  The threshold is different on different
   speeds of CPU and system-load.  The lower the threshold; the greater
   the performance but greater the risk of underrun.  The highest I've
   seen it go is 6 adjustments.

If you watch carefully; You can observe a red and blue shift while the
card *floods* an ethernet... :-) :-)


(now to Magnum-ify it.....)                           |  NovAtel Commnications Ltd.                               | <nothing I say matters anyway>
       <NetBSD: A drinking group with a serious computing problem!>