Re: Some ideas about new features of grub

[Felix Zielcke <fzielcke@z-51.de>]

Am Samstag, den 11.07.2009, 18:20 +0200 schrieb Michal Suchanek:
> 2009/7/11 Bean <bean123ch@gmail.com>:
> > On Sat, Jul 11, 2009 at 5:27 AM, BandiPat<magicpage91@earthlink.net> wrote:
> >> Actually Zenwalk provides os-prober as well.  The gentleman that provides
> >> the installer of our Grub2 uses os-prober to detect all OS's installed, so
> >> they may be added to the original grub.cfg.  Works very well, although not
> >> perfect, but we are pretty pleased with the results thus far.
> >>
> >> We also do not have to run any of the Grub2 programs after installing new
> >> kernels.  The developer of our installer patched Grub2 for Zenwalk, so that
> >> no changes were necessary after kernel updates.  He tried to offer this to
> >> you guys as well earlier, but got little response, so we use it for Zenwalk
> >> exclusively at the moment.
> >
> > Hi,
> >
> > IIRC, os-prober is a collection of shell script to detect os, but grub
> > already have them in util/grub.d. This method is based on linux, so
> > you need to enter linux in order to update the menu. On the other
> > hand, lua script generate the menu inside grub, there is no need to
> > enter any os.
> >
> > Another problem is the drive number. It's impossible to decide bios
> > drive number from inside linux, so we can't insert the correct
> > drivemap command required to boot DOS/Windows from secondary drive.
> > This information must be gathered at boot time.
> >
> 
> The other problem is that scripts like os-prober that use linux
> filesystem code for probing filesystems destroy your data.
> 
> Linux cannot mount journalled filesystems readonly. It always modifies
> them. The extent of the modifications and the impact may vary
> depending on the state of the filesystem (clean/mounted) and the way
> you are going to use it in the future (resume the system/fresh boot)
> but until Linux people implement readonly filesystem support any Linux
> based os-probers cannot be recommended.
> 

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/filesystems/ext3.txt;hb=HEAD
ext3 has a noload option which disables journal recovery and with
ro,noload used it's really read-only.
I think it was added recently with 2.6.30 or something like that.
-- 
Felix Zielcke