On Thursday 24 April 2008, reader@(protected):

> So assuming I've made some mistake in grub.conf I try to boot from
> grub command line.
>
>  root = (hd0,0) (which is /dev/sda1 in linux terms)
>
>  kernel /kernel-2.6.25-r1

Nope. Kernel needs a root=<device> parameter. It can't know what is your
root partition, that info is in fstab and fstab is on the root
partition.So you tell it via a parameter

> boot
>
> But it fails with a message saying please append a working root=?? to
> the boot commands.

expected result. see above.


> So reloading the install ISO I mount /mnt/gentoo/boot and edit
> grub.conf to say:
>
>   title=kernel-2.6.25-r1
>   root (hd0,0)
>   kernel /kernel-2.6.25-r1 root=/dev/sda3
>
> That fails
>   kernel /kernel-2.6.25-r1 root=/dev/hda3 (Thinking maybe grub
>   does not understand sda)

Nothing to do with grub. It's a kernel boot parameter passed verbatim to
the kernel and needs valid kernel device names.

What's the error you get? Is (hd0,0) a separate /boot? Does it contain a
file called kernel-2.6.25-r1 at the top level? And you also should have
a "ro" kernel parameter in there

> That Fails
>
>  kernel /kernel-2.6.25-r1 root=(hd0)/sda3
>
> Fails

Won't work. (hd0) is a grub thing. You need a /dev/sda3 or similar in
there

> I've even tried:
>   kernel /kernel-2.6.25-r1 root=(hd0,2)

Won't work. Same reason.

> And another failure... all with the same message about appending a
> working `root=???'
>
> I'm about out of ideas here.

here's a working grub.conf for illustration:

default      0
timeout      10
splashimage=(hd0,0)/grub/splash.xpm.gz

title       Default
root        (hd0,0)
kernel       /vmlinuz root=/dev/sda3 ro

title       Gentoo-2.6.25
root        (hd0,0)
kernel       /vmlinuz-2.6.25-gentoo root=/dev/sda3 ro

Seems my setup is identical to yours:
/boot on /dev/sda1 aka (hd0,0) to grub
/ on /dev/sda3

Only difference is the "ro" boot parameter, which shouldn't make a
difference - it's there for fsck purposes during start-up.

What disk driver and disks do you have? Are you 100% sure you are either
using the new ata driver (everything is an sd) or have scsi/sata disks?
If your disk is IDE with the old driver, it will be an hd and will
require that on the kernel line

--
Alan McKinnon
alan dot mckinnon at gmail dot com

--
gentoo-user@(protected)