GRUB Problems After Installing 2nd Hard Disk
Posts: 61
I encountered a problem with GRUB after installing a 2nd hard disk on my new computer. I have a very typical dual-boot setup. The machine has a 250 GB SATA disk, which MEPIS recognizes as SDA. Windows is installed on SDA1 and MEPIS root is installed on SDA5.
Yesterday, I installed a 120 GB IDE hard disk I had removed from another machine. The disk will be used as a back-up disk. MEPIS recognizes this disk as HDC, since I installed it as master on the secondary IDE controller. After I finished setting up the drive with Seagate Tools, I restarted the machine and got an error at the GRUB screen. Apparently, GRUB began looking for an operating system on HDA1, which doesn't exist! I hadn't made any changes to GRUB throughout this process -- it just started behaving that way on its own -- although I did change the BIOS by moving the IDE disk after the SATA disk in boot order (BIOS put the new disk at the top of the boot stack by default because it had a lower controller number).
I easily fixed the problem by booting the computer from the handy MEPIS Live CD and re-installing GRUB on the SATA disk. Now everything is fine. But my question is, why and how did installing the 2nd disk alter GRUB? Has anyone else encountered this kind of thing?
Computer: HP a1630n Pavilion
Factory OS: Windows XP Media Center
Now I understand ...
Posts: 61
Thanks, AdrianTM for yet another timely and informative response. I hadn't realized that BIOS communicates disk information with GRUB as (hd1,*) and (hd0,*). It now makes sense that changes to BIOS could trip up GRUB. Thankfully, the MEPIS Live CD has the right tools to fix things such as this!
Cheers,
joany
From what I understand It
Posts: 4077
From what I understand It didn't actually change GRUB, BIOS got different and served different drive numbers to GRUB as you said "BIOS put the new disk at the top of the boot stack by default because it had a lower controller number".
Something similar happens when you install GRUB on MBR of secondary disk and then you boot from that using BIOS option, BIOS will report to GRUB that that's the first disk while GRUB will still look for a secondary disk. I know this because it happend to me, that's why I wrote this:
www.mepis.org/docs/en/index.php/Installing_GRUB_on_the_MBR_of_a_second_drive
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