[This message was held for moderation because the mailing list software doesn't recognize <schaefer@...> and <schaefer+centos@...> as equivalent. That was last Friday, but still no sign of the moderator dealing with it, so I'm resending.]

Cutting straight to the chase:

When, if ever, does the installer offer an option to upgrade an existing installation, rather than wanting to reformat the disks?

More details than you may want:

I recently acquired a new PC chassis, with no operating system but with a Serial-ATA disk (which I was not expecting when I ordered it). I set the BIOS for legacy IDE mode and installed RedHat 9, then attempted to upgrade the kernel to add SATA support, without much luck.

Searching for the SATA driver modules I found CentOS and decided to try it. I downloaded the three ISO images to another PC, burned CDs, and set about to upgrade my RH9. However, the installer never offered me the option of upgrading (keeping my existing filesystems) -- no matter what steps I tried using when starting the installer, by the time it got to the page for disk partitioning it always wanted to start from scratch and blow the existing partitions away.

I finally concluded that I hadn't put anything important on the disks during my struggle with RH9, so I went ahead with the clean install. Everything is working nicely at this point, so thanks for that.

However, there are some other RH9 systems around the office that may need to be upgraded at some point, and they definitely can't be wiped clean in the process. Is there a way to upgrade from RH9 to CentOS?

Any remarks about upgrading from even older RedHat releases?