Added an additional hard drive.....

[jgutty]

....now have 1 TB yeah!

It is my 3rd SATA drive in this box. All is well, but I am puzzled.

Before the new drive was added I had windoze on sda, F9 on sdb, grub on sda.

When I booted the 1st time after adding the 3rd drive, gparted showed the new drive as sda, windoze as sdb, fedora as sdc. grub.conf reflected things as they were before. After formatting the new drive as a linux partition, I was hesitant to reboot without editing grub.conf to reflect the new designations as reported in gparted.

I did not change the conf file and all is booting with no issues.

Why does grub function under these circumstances? (Not that I am complaining)

[stoat]

Hello jgutty,

Interesting. To me, such a thing could occur because GRUB does not assign device names such as /dev/sda to drives. The operating system does that. GRUB relies on the BIOS to determine its device designations such as (hd0). At the time GRUB is going about the business of booting the kernel, that BIOS order is all that really matters because the operating system hasn't started. Since it is not unheard of for operating system device names and GRUB drive designations to get sort of mixed up, maybe the addition of your new drive resulted in the operating system reassigning device names, but the BIOS drive order with the new drive was such that it did not result in a misconfiguration of grub.conf. And thank goodness for partition labels and/or UUIDs in /etc/fstab, I guess.

Where you might have some problems with all of this is if you now needed to re-install GRUB in the master boot record and were to use the grub-install command. The grub-install command always consults the device.map file if the --recheck option is not used (the device.map's only purpose), and it probably still has /dev/sda mapped to (hd0). You can either remember that fact or change the device.map file to match the new reality now in your head. It's what the device.map file is for. It does not have any effect on routine booting whatsoever.

I guess if you decide that you don't like what has happened, you could try playing with controller cables or udev rules.

[jgutty]

That makes sense to me. Thanks for the insight. I edited the device map file as you suggested, hopefully it will not be needed.