> 
 > > >  If you do that, then you can not do NFS root over PPP/SLIP,
 > > >  (with BOOTP) which was intended to work.  Does anybody care?
 > > 
 > > while i doubt i will ever use this feature, it _should_ exist.
 > 
 > What does it _mean_ to mount root via NFS over a PPP or SLIP
 > interface?
 > 
 > How do you set up the SLIP or PPP connection?  How do you set up the
 > kernel line discipline on the right tty?  What does bootp over SLIP or
 > PPP really "mean," to begin with?
 > 
 > Even forgetting the performance issues, NFS root mounted over SLIP or
 > PPP seems nonsensical.

Last time I looked at the netboot code, which was a while ago, it chose
an interface by looking for one that supports broadcast. A lot of stuff
is just wired for ethernet.

But as silly as it might seem over a tty line, there are four or five
arp-less point to point serial and parallel links used mainly for
parallel computing, these are all over 800 Mb/S (Avalon's is 3.2 Gb/S)
and would run NFS just fine. Nodes with 3 Gb/S links don't need local
disks.

Bootp should work OK over non-ethernet links. Unlike arp, it is encapsulated
over UDP and there is the bootpgw stuff to forward requests over subnet
boundaries.

As a fix, its fine for now, as other things presently prevent non-
ethernet netboot and it is trivial to undo.  But arp-less netboot will be
required by us soon, and by others eventually, so work on a more
general approach would not be wasted.
----------------------
Ross Harvey	Avalon Computer Systems, Inc.		  ross@teraflop.com
		Santa Barbara	 		    http://www.teraflop.com