Re: Idea: Single-time setting change

[Pavel Roskin <proski@gnu.org>]

On Sun, 2008-07-06 at 19:55 +0000, Jago Pearce wrote:
> Simply add an option to so that the
> default boot can be changed to something, but then changes back to it\'s
> original setting after that boot.
> 
> This way I can create an option of
> `Reboot into Windows`, walk away for a coffee and find it sitting in Windows or
> other o/s ready for me.
> 
> Unless perhaps there is already a way to do this?

It's a good idea, but there are some corner cases and details to be
worked out.

The most flexible approach would be to allow the user to select both the
default and the entry for the next boot, both at the boot time and from
the host OS.  At the boot time, we should strive to make it possible
entirely from the menu.  Yet we want the manually selected entry to be
remembered as default if no default was designated.  And we should try
to implement the fallback functionality from GRUB1.

It looks like we need 3 variables to be recognized:

nextdefault - default at the next boot.  Must be unset at the next boot.
default - the default entry unless nextdefault is set.
fallback - the entry to use if both nextdefault and default fail.

We need a key in the menu to set the default (and possibly to set
nextdefault and fallback).  The menu should export default and selection
to the GRUB scripts.  I think the "savedefault" command should do the
right thing without any options.  Or it should be coded in the GRUB
script.  Or it should be implicit (less desirable).

-- 
Regards,
Pavel Roskin