Re: chain loading USB harddrive if no native USB support possible?

[Franklin PIAT]

On Fri, 2008-04-04 at 16:10 +0200, Michael Reichenbach wrote:
> Franklin PIAT wrote:
> > On Fri, 2008-04-04 at 05:51 +0200, Michael Reichenbach wrote:
> >> I have a comp here without native USB support. The bios can not boot 
> >> from USB directly. Booting from CD, HD and floppy works.
> >>
> >> In grub shell with null ( I also does not see the device, only the 
> >> internal harddisk.
> >>
> >> On google I did already found instructions to successfully chain load CD 
> >>   with grub.
> >>
> >> Isn`t this possible also for USB? I mean, first boot grub from cd or 
> >> floppy, then load a linux kernel, he makes the USB device usable and 
> >> then chain load USB?
> > 
> > I guess that nothing prevents you from installing grub on a floppy or CD
> > with its config file. The tricky part will be to tell grub to search for
> > a given file, in order to identify the [USB] root device.
> 
> Yes.
> 
> > Under grub2, you can use the "search" command (read [1] for more
> > information).
> 
> Well, yet I have only learned grub legacy because I mostly use the 
> "latest stable" and also most documentation was for it. However, if 
> needed I will also look inside grub 2.

Grub v1 may have similar feature, check the manual.

> My question is now the following. You mean grub2 can detect and boot 
> more devices then grub legacy?
> 
> (supergrub with grub legacy did not find the device)

It probably depends on the scenario (grub2 has more features, but a few
regression too).

> > I haven't tested, but if you label the USB device with a unique name,
> > then a script like this should work:
> >  search -f MyUsbLabel
> >  linux      /boot/vmlinuz root=LABEL=MyUsbLabel ro
> >  initrd     /boot/initrd.img
> 
> This means it`s only possible to boot linux that way? Chan loading 
> another bootloader directly isn`t possible?

I don't know. Maybe someone else can answer this question.

Franklin