[Techtalk] I lost my filesystem
Robyn Manning
rmanning at adam.com.au
Tue Apr 15 02:06:41 EST 2003
> How familiar are you with GRUB? GRUB reads filesystems and kernel executables,
> rather than inflexibly restricting the user to disk geometry. It uses a
> different partition numbering scheme than fdisk, GRUB starts from 0:
>
> /dev/hda1
> /dev/hda2
> /dev/hda4
>
> translates to
>
> hd0,0
> hd0,1
> hd0,2
> A second hard drive is hd1, and so forth..
>
> GRUB can find the boot partition and kernel. At boot, hit C to get to GRUB's
> command line. To boot manually, you need 3 things: root, kernel, then the
> 'boot' command. Use tab completion to find the root and kernel values. Type
> the known value, in your case hd1, then keep hitting tab until something
> happens:
>
> #use tab-completion
> grub> root (hd1,
>
> GRUB will respond something like this:
>
> Possible partitions are:
> Partition num: 0, Filesystem type is reiserfs, partition type 0x83
> Partition num: 1, Filesystem type unknown, partition type 0x92
> Partition num: 3, Filesystem type unknown, partition type 0x17
> Partition num: 4, Filesystem type is ext2fs, partition type 0x83
>
> Enter the correct partition, yours is hdb2, so it looks like this:
>
> grub> root (hd1,1)
>
> GRUB will confirm:
>
> Filesystem type is ext2fs, partition type 0x83
>
> Now find the kernel:
>
> #use tab-completion
> grub> kernel /boot/vmlinuz
> Possible files are: vmlinuz vmlinuz-2.4.19
>
> Enter vmlinuz-2.4.xx, whatever yours is, plus append the correct root line.
> Notice the trickiness, on this line use fdisk-type values:
>
> grub> kernel /boot/vmlinuz-2.4.19 root=/dev/hdb2
>
> Enter the boot command:
>
> grub> boot
>
> If you found the correct root partition and kernel, it will boot. Then edit
> your GRUB boot menu, and there you are. Don't listen to people who tell you
> to change your partition labels, they don't know what they are talking about.
I was saying in my message that if grub was like lilo there was stuff in
the boot record that needed changing.
Thanks for the link to the tutorial on grub. I tried it about 1 1/2
years ago without a tutorial and couldn't fathom it. I'm quite happy to
try new things it's just that I learned lilo first that's all.
Robyn
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