sata HD, AHCI and opensuse 11.0

Asus P5Q Deluxe, core2duo, 3.0 GB ram, AHCI enabled,opensuse 11.0, 3 Sata internal drives, 1 external USB drive, all installed and recognized.

I am having a problem adding a 4th sata internal hard drive to this system.
Other than minor problems [none hardware related since I switched to AHCI mode in BIOS]this mainboard works well with openSuse 11.0.
There are 5 regular sata connections on the mainboard and three others that have to do with Raid?, mirroring and stuff I don’t know about. My existing hard drives are labelled by-id in the opensuse partitioner:
sda1, 2, 3 contain my swap, root and home stuff [80GB]
sdb1 is storage [320GB]
sdc1 is storage [160GB]
When I plug my 4th drive into the machine, it does not show up in the partitioner and all of a sudden what was shown as sda1,2,3[swap,root,home] is now shown as sdc1,2,3, while my sdb and sdc drives are now shown as sda and sdb.

What is causing this and what can I do to correct it and get this 4th drive installed?

p.s. as an added note: In the partitioner sdb1 shows as having 320GB, but when I look at “My Computer” on the desktop, it only shows as 147GB.
[If this is a separate problem, please tell me to post elsewhere]

It is logical that the numbering (rather lettering) changes, because they are given out during boot in the sequence they are found and you have somewhere in between put something new. That is exactly the reason why you find them in /etc/fstab mounted by-id. When you do

ls /dev/disk/by-id 

in the old and in the new situation you will see that the same scsi-…-part1 is a a symbolic link to /dev/sdb1 in one situation and a link to /dev/sda1 in the other (these are not your values, but I hope you understand how it works). One could also youe /dev/disk/by-label, but openSUSE uses by-id by default. (more: SDB:Basics of partitions, filesystems, mount points - openSUSE

Please, with this knowledge now try to find out if you are still missing a disk, and when yes, which one. Look to their ids in /dev/disk/by-id, not to /dev/sda, /dev/sdb, etc, because that is dynamic.

ty hcw

I am reading the : SDB:Basics… now and hopefully it will give me a better understanding of how opensuse handles hard drives.
I seem to continually have problems adding/removing hard drives from both my machines [both on opensuse 11.0]. I cringe when I find I need to add/remove one. Gladly, it does not happen often.