Re: Status of UNDI Support

[Marco Gerards <mgerards@xs4all.nl>]

didi@tau.ac.il (Yedidyah Bar-David) writes:

> On Fri, Mar 10, 2006 at 03:07:36PM +0100, Marco Gerards wrote:
>> Martin Vogt <vogt@itwm.fraunhofer.de> writes:
>> > Isnt it possible to re-use some UNDI support from pxelinux and put it
>> > into grub2?
>
> While I do not know the internals of grub2, I guess some parts of it run
> in protected mode, while pxelinux is realmode only. I think this means
> it won't be easy to use parts of it.

GRUB is able to switch to realmode and back.  It's what's done when
accessing the BIOS to read from disk.

>> 
>> I don't know.  I think it is better that we write it ourselves, it
>> does not appear too hard to implement...
>
> Looking at the sources of pxelinux, it seems somewhat more complex than
> what you can tell from reading the specs, mainly because you want, as
> reasonably as possible, to support also buggy PXE stacks etc. So while
> it's probably not that hard, it would make sense to look at pxelinux for
> reference if not for the code.
>
> I personally was a user of both etherboot, grub with etherboot drivers
> and grub with undi (which indeed did not work well for me back then - I
> did not try it recently), and I agree it would make more sense for grub2
> to support undi only, unlike grub legacy which tried to support
> everything etherboot supported, which was probably too much
> synchronization work and therefore did not work well.

I prefer to support both.  The etherboot drivers usually work better
than UNDI, AFAIK.  But when etherboot does not support a card, people
can fall back to UNDI.  Don't forget that not all cards support UNDI,
so I don't want UNDI only.

--
Marco