disk problems: which ATA?

[Ross Boylan <RossBoylan@stanfordalumni.org>]

How can I tell which ata device is which hard drive?  It's come up
several times for me, most recently with
ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen

It appears from other info that sdb is the problem:
<terminal>
# smartctl -H /dev/sdb
Sun Jul  3 10:26:29 PDT 2011
smartctl version 5.38 [i686-pc-linux-gnu] Copyright (C) 2002-8 Bruce
Allen
Home page is http://smartmontools.sourceforge.net/

Short INQUIRY response, skip product id
A mandatory SMART command failed: exiting. To continue, add one or more
'-T permissive' options.
</terminal>
but I'd like to know how to do this in general.

I'd also welcome advice about the disk problems, but I was hoping to
raise the odds of an answer by keeping it simple :)

sdb has had hardware problems for awhile; it wouldn't be surprising if
it's failed.

Running lenny with linux 2.6.26-2-686.

Thanks.
Ross