[TriLUG] [eee] post-install, grub OK from external stick but not from internal SSD

[Brian McCullough]

On Thu, Apr 24, 2008 at 06:22:49AM -0700, Joseph Mack NA3T wrote:
> On Thu, 24 Apr 2008, Tom Roche wrote:
> 
> > (hd0) /dev/sda
> 
> kernel device /dev/sda is known as (hd0) by the BIOS
> 
> > * SSD's /boot/grub/menu.lst has
> >
> > title Normal Boot
> >         root (hd0,0)
> 
> this line is redundant, you have a root option in the next 
> line
> 
> >         kernel /boot/vmlinuz-2.6.21.4-eeepc quiet rw vga=785 irqpoll
> > root=/dev/sda1
> 
> you don't have a disk here. Presumably grub will default to 
> (hd0,0). It would be better to explicitely state a disk.

The / is taken by grub to be the "boot device".


> again no disk specified. presumably will boot from (hd0,0)

Actually, although I don't remember seeing what device the stick is, I
would imagine that it is booting from (hd1,0).



> > root=UUID=45037d5d-b0f4-4d19-b00c-4f4aebc84a02 ro quiet splash
> 
> you risk a collision with the root line above. This seems a 
> complicated and error prone way of describing a disk. Is 
> there a reason you don't want /dev/sda1 or (hd0,0)?

He didn't do that because "modern" usage is either through disk-Label or
UUID.  That way you can change disk order without messing up your root
device.  Although I tend to still use /dev/(sh)da..., I have seen this
in recent installations of Ubuntu, et al.

BTW, is "ro quiet splash" appropriate here, and not on the kernel line?



> > # This entry automatically added by the Debian installer for an existing
> > # linux installation on /dev/sda1.
> > title           Normal Boot (on /dev/sda1)
> > root            (hd1,0)
> 
> does the BIOS know about (hd1,0)? is it in device.map? I 
> assume it's your flash stick and will be /dev/sdc1 after the 
> kernel boots.

I am also presuming that grub will identify the stick as (hd1,0).  This
is the value that you want in your SSD menu.lst.

Incidentally, you ( not Joe ) ask about how to fix these values, and not
have to edit them manually each time you boot.  Simply edit the menu.lst
or grub.conf file in /boot on each device to have the correct values.


> > kernel          /boot/vmlinuz-2.6.21.4-eeepc quiet rw vga=785 irqpoll
> > root=/dev/sda1
> 
> boot from (hd0,0), mount /dev/sda1 as root, which collides
> with the /dev/sdc1 above


Are you sure this isn't the entry for the hard drive ( SSD )?  /dev/sda1
would be appropriate for that.



Brian