Re: change default os

[David WE Roberts]

On Wed, 13 Mar 2013 11:52:57 -0700, Jordan Uggla wrote:

<snip>

> 
>> An alternative way is to re-order the components in /etc/grub. On my
>> Debian system, Windows (and others) are detected by 30_os-prober - if
>> you change the numbering so this comes before nn_linux, then the
>> Windows OS will come before Linux in the list, meaning Windows will
>> boot by default. You'll need to take care to deal with this change any
>> time Grub gets updated and the installer wants to put new config files
>> in.
> 
> Hence it's hardly worth mentioning. I highly recommend against doing
> this. My general feeling is that you should never make any changes in
> /etc/grub.d/ at all (only modifying /etc/default/grub is enough for 95%
> of people, and for 4 of the next 5% adding custom entries via
> /boot/grub/custom.cfg is enough). If you're in the 1% that can't get
> what you need/want from grub-mkconfig without modifying /etc/grub.d/
> then I would recommend writing your grub.cfg completely manually.

I have used the renumbering trick on several systems for some time and it 
seems to work fine.

Changing the order in which the '.d' files are run seems to change the 
order in which the menu entries are built and is less invasive than 
editing config files.

Given that the grub.cfg file starts with an explicit warning against 
editing it directly, as does the documentation, I an confused as to how it 
is a viable alternative.

Please note that I am running Ubuntu Linux.

On a regular basis the kernel is updated and the grub configuration is 
updated.
So writing a manual grub.cfg would surely mean redoing this every time you 
updated the kernel.

I haven't yet seen grub.d updated (at least not os_prober).

This fix is quite widely mentioned in Linux fora (which is where I found 
it).

So you will have problems if /etc/grub.d is updated or restructured such 
that a new os_prober script is delivered.

How often is this compared to kernel updates?

So I note your great lack of enthusiasm for this method, and I appreciate 
that it may not be obvious that grub.d has been updated until you start to 
have problems with your grub boot menus (such as the same OS appearing 
twice) but I would appreciate a view on how often this is likely to be a 
problem.

For the less technical user this seems a neat solution to the problem.

On a more abstract note, why should Linux appear before 'other OS' in the 
boot menu?

It would be much more friendly if you could select the order in which 
various OS are added to the menu, to cope with the situation (as we see 
here) where Windows is the default operating system of choice but Linux/
grub keeps on insisting on taking first place each time updates are 
applied.

Just suppose you wanted the menu order to be

(1) Windows 7

(2) Windows Vista

(3) Linux

How would you achieve this automatically on a kernel update by Ubuntu?

Cheers

David