devfs and hot unplugging

[M. L. Dodson]

I was transferring a bunch of data files from compute nodes to a server 
using dump-restore.  I put the disks with the data files into an external 
firewire device, plugged it in, and did the transfers.  This is on 
6.1-RELEASE-p6.

When I finished the transfers, I just pulled the cable (the firewire disk 
partitions were not mounted).  When I plugged in the next drive, devfs 
created devices with names like /dev/da0s1aa, /dev/da0s1ab, /dev/da0s1ac, 
etc., in addition to the regular /dev/da0s1a, etc (which were left over 
from the first disk, they were not destroyed when I pulled the cable).  
When I tried to fsck the firewire disk partitions, /dev/da0s1a 
and /dev/da0s1g worked fine (as did the dump/restore from /dev/da0s1g).  
The other partitions, /dev/da0s1d, e, and f, failed, saying the superblock 
could not be found.  All the data disks were of the same kind and had 
identical partitioning schemes.

My question: Should I be doing something to signal devfs I'm going to unplug 
a device so it won't get confused when I plug in another similar, but not 
the same, device?  What's going on here?

Bud Dodson
-- 
M. L. Dodson
Email:	mldodson-at-houston-dot-rr-dot-com
Phone:	eight_three_two-56_three-386_one