On Fri, 21 Mar 1997, Mark Routbort wrote:
> sn0 at obio0sbc0 at obio0: options=1<PDMA>
> ^^^^^^^^^^^^
>
> However, no sn0 interface shows up with ifconfig -a:

It seems that SONIC is detected, but not attached to the kernel.
The current maintainer of if_sn might make some mistakes.
It might be better to check the I/O addr where the SONIC registers  
are mapped.

I'm one of workers on if_sn, but I don't have time to debug the  
driver in -current for the moment.
Anyway, I put my custom kernel for PB550c on a ftp site.
It is working nicely on my PB550c at least.

It is available from:

ftp://ftp.aa.ap.titech.ac.jp/pub/yanagisw/NetBSD/netbsd_PB550c_SONIC. 
tar.gz
(If you can't resolve the IP address, try 131.112.71.130 instead.)

Good luck!

---
Takeshi Yanagisawa <yanagisw@aa.ap.titech.ac.jp>

Dept. of Applied Physics, Tokyo Institute of Technology,
O-okayama 2-12-10, Meguro-ku, Tokyo 152, Japan
"...And you'll see why 1997 won't be like '1997'."