Re: [PATCH] search -d|--disk

[Robert Millan <rmh@aybabtu.com>]

On Tue, Jun 23, 2009 at 05:17:22PM -0400, Pavel Roskin wrote:
> > 
> > QEMU has a feature in which you can specify the boot drive from command
> > line (-boot parameter).  After i386-qemu port is merged, I plan to add
> > some code to read this from CMOS and export it to some variable.
> > 
> > When on GRUB, it is up to the user to decide what "boot this drive" means.
> > An interesting option is to search for a specific file in the disk we're told,
> > and then act upon it (e.g. configfile /grub.cfg, multiboot /grub.elf,
> > linux /vmlinuz, whatever).
> 
> I think the convention is to load the first sector of the disk.

That's the BIOS convention, which is useful when there's a BIOS.  Otherwise
there isn't much you can do with 512 bytes of code.

> Maybe we could pass
> environment variables using some qemu facility.

Yes, qemu exports -boot parameter to CMOS, just like memory size.  GRUB can
read it from there.

> > I implemented it only for files.  It's trivial to do it for labels/uuids
> > too, but it's annoying because doing so results in code duplication.
> 
> Yes, it's annoying, but partial implementations are annoying to the end users.
> 
> Perhaps it should be possible to implement disk filtering using the
> mechanism used to skip floppies.

I'll see what I can do.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."