A simple problem that I had done for years, turned  out to be difficult due to 
a mistake I made and what I believe is an error in the Linux OS.
How you set it up is to forget to remove the logical drive from "/etc/fstab" 
in the past it was never a problem.
But in SL 5.5 it is a serious problem because during boot it can't find the 
drive name.  It drops you to a maintenance level and all you used to do in 
put in the root pass word, edit the files etc.
What happen now:
put in your password
"bash  /usr/bin/id:   no such file or dir"
"bash  [: =: unary operator expected"
"bash  /usr/bin/id:"
"bash [: =: unary operator expected"
"bash /usr/bin/kpg-config: no such file or dir"
>repair file system1
As a result you can do nothing because your passwd has been rejected.

You are back to using your install disks. It recognizes un initialized disks 
and initializes them - do a new install and set up disks and disk names and 
do not format anything, except new disk,  setup root / passwd, set up 
internet, do not install any thing.   and it knows there is an active OS 
present and the install aborts.

The system reboots and runs normally everthing is preserved all because some 
security nit modified the code and never checked the end result.
Sometime you can be so secure that the system becomes worthless.

What used to be a simple thing of replacing disks has now been difficult at 
best.   
What I fixed is to get rid of the logical names in in the fstab and went back 
to the /dev/sda1 etc.   This was done because I didn't have a good way to 
look at disks and their names but knew the hardware.

For back up on paper you need to do "df" and pipe it to lpr, keep in you file 
folder as a true back up.

You can easily create this problem by simply unplugging a disk and trying a 
reboot.   

I have three backups but I never had a disk that was good but the electronics 
became intermittent as a function of temperature.  suspect a bad solder joint 
or circuit trace crack somewhere.   The symptom was a nice running drive that 
was sluggish.   A reboot solved the problem but the failures began to 
increase.   Users don't seem to understand a system being down.
Some of these boxes are shut down ever six months for cleaning. 

Disks being cheep it time to install a new one and toss the old one.

Larry Linder