Re: lvm module can't see USB disks' volume group

[Alexandre Oliva]

On Feb 11, 2017, Andrei Borzenkov <address@hidden> wrote:

> Could you show exact message?

> Assuming the actual error was "hd0 cannot get C/H/S values",

I'm pretty sure that was it.

> it is output when INT13 AH=08 fails and disk does not support
> LBA (i.e. INT13 AH=41 or AH=48 failed previously as well).

> As BIOS is capable of loading core.img itself off this disk, it is
> obviously capable of working with it. So we need to figure out what BIOS
> returns and how to work around it. If you can compile GRUB we can try
> add debug output to see what happens.

I'll look into plugging debug messages at appropriate spots.

I don't suppose there's a GRUB module that enables one to issue INT13
commands interactively, is there?  That would make it easy to perform
interactive experimentation.  I suppose I could see whether FreeDOS has
the 'debug' command I used to use to do this on another OS back in my
pre-GNU days ;-) Those skills of mine have certainly grown rusty over so
many years, but looking at the GRUB code, I'm pretty sure I can still
figure out how to interact with the disks through the BIOS, and figure
out why GRUB can load core.img but not access disk partitions.

Thanks for the feedback so far.  Expect to hear back from me in the
not-too-distant future.

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer