[Grml-devel] grml - package report: Defaulf for findiso boot option

[Florian Kusche]

Hello Michael,

On 11.03.2010 23:49, Michael Prokop wrote:
>> is it possible to include a default value for the findiso boot
>> parameter in the initrd scripts? Something like "/grml.iso" would
>> be sufficient.
>>
>> Reason: Integration of grml into multi-boot-rescue DVDs would be
>> much easier. One could place the grml-ISO-image at the default
>> location on the DVD and just chain load from the boot menu of the
>> rescue DVD to the grml boot loader. Actually, it already works -
>> you just have to enter the ISOLINUX command line and enter "grml
>> findiso=/grml.iso". However, it would be nice, if that would not
>> be necessary.

> Hm you mean if the user is specifying findiso without any arguments
> it should use /grml.iso by default?

no, but instead:

> Or do you mean it should try to use /grml.iso really just by
> default in the default unmodified boot option?

Yes, this is what I meant.

> Whereas the first option doesn't bring any real benefits IMO the
> second option actually is quite risky. First of all because of
> possible unexpected behaviour as well as locating a possible wrong
> grml ISO, non matching kernel versions etc. (Yeah, we've a new
> mechanism to improve reliability for identifying the according boot
> device nowadays but it might become funny to debug in several
> situations anyway.)

But: If the user just burns the original ISO image, this can't happen. So the normal case would be safe anyway.

Maybe it would be a bit better to look for /grml.iso as a last resort just before bailing out to the initrd shell if grml.squashfs is not found in another way.

If you still want to add an additional safety layer against accidently mounting the wrong file system, I can think of two ways:
- search for the exact file name of the ISO (e.g, grml_2009.10.iso). However, then you have to make individual initrds for each ISO.
- check the contents of /GRML/grml-version.

This feature really would make it much easier to create combined rescue DVDs that contain several operating systems.

> I do prefer explicit configuration in this situation, but adding

I understand that - but please consider that it would make it much more convenient for a lot of users not having to know about the "findiso" boot option and not having to enter it (...especially with a non-US keyboard layout).

Regards,
Florian