Re: Treating .old Linux kernels

[Robert Millan]

On Mon, Dec 31, 2007 at 02:59:59AM -0500, Pavel Roskin wrote:
> Hello!
> 
> I have adjusted grub-update to pick up initrd on Fedora.  Fedora uses  
> different filenames.  The version goes before ".img", not after, e.g.  
> initrd-2.6.24-rc3.img
> 
> I'd like to get an opinion on treating old kernels.  If the kernel is  
> installed and there is already a kernel with the same version, the  
> original kernel is renamed by adding ".old" to the filename.  The old  
> initrd is not preserved.
> 
> Currently, grub-update (more specifically, util/grub.d/10_linux.in)  
> treats ".old" as part of the kernel version, so it fails to find the  
> correspondent initrd.  Therefore, an entry is created without initrd.   
> In case of Fedora, it won't boot unless the device files are present  
> on the root filesystem under /dev (they need to be copied).
> 
> I think ".old" kernels don't need to be in the menu. The existing  
> entry can be edited to use the old kernel if the new kernel fails to  
> boot.  It's not a normal situation, it's an emergence, and it's where  
> GTUB shines.  Another approach would be to use the new initrd if the  
> old initrd is not found.  Leaving things as is would be misleading,  
> because the old kernel would fail to boot on many systems, leaving a  
> wrong impression of safety.
> 
> Thus, I see such options:
> 
> 1) Don't add old kernels to the menu
> 
> 2) Keep adding old kernels to the menu, but try harder to find the  
> suitable initrd for them.

I don't have a strong opinion on this, but I'd opt for trying harder.  Skipping
.old breaks compatibility with existing update-grub that is provided with
Debian (and derivatives) for GRUB Legacy, which means there's a big userbase
that has come to expect this behaviour.

Not that I care much about compatibility in the proper sense of the word, but
rather about output that is visible to the user.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call, if you are unable to speak?
(as seen on /.)