Re: [DRAFT] Policy for Linux kernel, initramfs, boot loader update process

[Stephen Powell <zlinuxman@wowway.com>]

On Wed, 30 Jun 2010 10:54:53 -0400 (EDT), Jonas Smedegaard wrote:
> On Wed, Jun 30, 2010 at 10:31:32AM -0400, Stephen Powell wrote:
>> dpkg does not prevent multiple boot loaders from being installed
>> concurrently; but this environment is not supported by the various
>> system maintainer scripts of Debian, even today.  For example,
>> "update-initramfs -u" currently checks to see if lilo is installed,
>> and if it is, it runs lilo.  But if grub (either version 1 or version
>> 2) is installed also, it issues the following messages:
>> 
>>    WARNING: grub and lilo installed.
>>    Please de-install unused bootloader.
>> 
>> It could also test for other boot loaders as well, such as extlinux,
>> but it doesn't.  The point is that Debian's maintainer scripts
>> do not support multiple concurrently-installed boot loaders even today.
> 
> I read above as initramfs-tools in particular not supporting multiple 
> bootloaders.
> 
> Could you perhaps elaborate more on why this is a general problem?

I think Max has answered that question, as least as it pertains to
initramfs-tools.  To generalize from that, it makes it difficult for
various tools to know what to do or to co-ordinate with each other.
For example, only one boot loader can own the master boot record.
So if two hook scripts starting with "zz-" are installed,
one for each boot loader, what happens?  The last one to execute wins?
That's not going to work.

Let's turn that question around.  What legitimate purpose is served
by having multiple concurrently-installed boot loaders?

-- 
  .''`.     Stephen Powell    
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