>1) Does NetBSD support IP over ATM (or direct ATM using e.g. sockets)
?

I know of no drivers, and there is little kernel support (if any) but
it would be nice to have.  ;)

>2) Does NetBSD support any serial cards (apart from standard 16550
UARTs)

Yes.  Some multiport cards are supported.  I'm not certain which, but
it should be in the install doc.

>3) Can NetBSD drive two UTP-ethernet cards, connected back-to-back, at     
>   full 10 Mbps speed simultaneously (i.e. bypass the transeivers standard
>   'I-listen-to-the-line-to-detect-colisions')

That would seem to be a card dependant feature.  I suspect most cards
will not allow that -- the ethernet protocol would be where that is,
not the driver for NetBSD.  If you have sample code to do this, it
should be trivial to add to NetBSD.

I can reach about 7.9Mbps over a link with only two computers on it.
This is better than SGI Indys can do.  They only get about 7.3Mbps  ;)
The reason for the problem is, of course, the collision.  However,
turning it off isn't right for two reasons.

1)  It breaks the ethernet protocol

2)  It won't help.  Even in 10baseT the ethernet is still viewed as a
bus, where transmit and receive cannot both be done.  I.e, you can't
have two full streams running over the wire, even when directly
connected.

If you are talking about ATM over UTP, I don't know of a machine that
can do 155Mbps even at work.  I've seen a maximum of about 63Mbps
between two Indys and even with one Onyx talking to another Onyx.

--Michael

--
Michael Graff <explorer@flame.org>        NetBSD is the way to go!
PGP key on a key-server near you!         Netshade the world!