Re: GRUB device names wrt. ieee1275

[David Miller]

From: phcoder <address@hidden>
Date: Sun, 22 Mar 2009 01:41:52 +0100

> Device name in boot block will anyway be written in it's complete
> raw OFW form, no matter how the rest of the grub2 accessing the
> disks. Using UUIDs in this place would be nice. On IRC you said that
> we have 120 bytes for the name. UUID is 16 or 32 bytes depending on
> FS. Is it possible to fit something like <read first sector> of
> every disk, <compare data at given offset>?

This is possible, but I know that Solaris folks would like to use the
Sparc GRUB support I'm writing and I'm not so sure whether they have
FS UUIDs or not.

> I don't agree that all devices should be accessed exclusively by
> UUID. It makes things difficult to maintain because of internal
> naming. IMO quoting and escaping offers the best universal
> solution. I don't see why sth like
> (/address@hidden,600000/address@hidden/address@hidden/address@hidden/address@hidden/address@hidden,1)
>  is a
> problem. Anyway you don't type such a thing manually and probably
> use tab-completition instead

We could use escaping, sure.

Actually most of the time users use device aliases, however:

1) GRUB should work when a device lacks a alias.

2) GRUB should keep working even if the user deletes one of
   the aliases.

While convenient I'm not so sure that OF device aliases are
a good basis for the names GRUB should use because they are
by their very nature transient.

It does take quite a bit of effort to translate between different
OS device naming formats into OF native ones.  So whatever universal
naming convention is choosen, it should be such that it can be
mechanically and statelessly converted to OF.