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Re: Grub option on Debian-style install

>> The original question was that I do not know what knoppix-installer is
>> going to do to my boot setup - specifically the second option, since
>> the MBR overwrite seems clear. It hasn't done it yet because I don't
>> know what it is going to do. That is what I'm asking: what does it do?

> Frankly, the right person to ask would be Fabian Franz who wrote the
> installer script. It always confuses me, and I don't really know why and
> under which circumstances it is working. ;-)


> But as it looks, the following is being done:

>         case $BOOT_WHERE in
>                 partition)
>                         grub-install
> --root-directory=$TARGET_MNT_POINT "$HD_CHOICE" >/dev/null
> 2>/dev/null || \
>                         grub-install
> --root-directory=$TARGET_MNT_POINT "$HD_CHOICE" >/dev/null
> 2>/dev/null
>                         ;;
>                 mbr)
>                         grub-install
> --root-directory=$TARGET_MNT_POINT "(hd0)" >/dev/null 2>/dev/null
>                         ;;
>         esac

> Which probably means that grub is installed on the partition record, not
> the master boot record, in case you select "partition".

I presume you mean "in the case where you select 'partition'". Yup,
that's what happened in my case.

> This will not work for all file systems, since not all of them have
> additional space in the filesystem header for installing a
> bootloader. ext2 and reiserfs should be safe, but I can't tell what
> happens if you try this with xfs or jfs. It seems that Fabian forces
> installation on the master boot record in these cases

Aaargh! Thank goodness I chose ext3. This was precisely what I wanted
to avoid. So, danger lurked even though I thought I was safe.

> which I think it not a good idea when the user had selected
> "partition" before.

Indeed not. That's horrible,

>> What you describe is where I want to get to, but I'm not going to
>> press the button on the installer until I know what it is going to do.

> To be absolutely sure, you would have to read all parts and modules of
> the installer script, check /usr/sbin/knoppix-installer and 
> everything under ./usr/share/knoppix-installer/*...

>> To repeat:
>> Clearly, I don't want to overwrite my existing MBR, since I want point
>> to the scrip in Debian's /boot/grub script. However, I don't know what
>> will happen should I select the second option. What I actually want to
>> do is add a knoppix line to my existing grub script.

> I hope the above sheds some light, and the "partition" option should be
> safe - except if the file system on the partition in question is xfs or
> jfs in which case it looks like the MBR is overwritten regardless of the
> users choice. I found this out by studying "boot-tools.bm" from Fabians
> installer.

It'd certainly be a good idea to change that script to avoid
overwriting someone's MBR. That could put someone off Knoppix, even
Linux, for life - which is clearly not your intention.

> You will probably still have to change your grub configuration manually.

Yup, that's what I wanted. It was easy enough to copy the grub items
from the Knoppix install into my grub menu script - although I don't
know what the difference is between the two entries:

title           Debian GNU/Linux, kernel 2.6.12 Default
kernel          /boot/vmlinuz root=/dev/hdc6 ro ramdisk_size=100000 lang=en apm=power-off nomce acpi=off vga=791
initrd          /boot/initrd.img

title           Debian GNU/Linux, kernel 2.6.12
kernel          /boot/vmlinuz-2.6.12 root=/dev/hdc6 ro ramdisk_size=100000 lang=en apm=power-off nomce acpi=off vga=791
initrd          /boot/initrd.img-2.6.12

Any takers?

> The absolutely safest option would probably be to install NO bootloader
> (if that's an option)

No, it's not - and I agree that it should be. It's nice to have the
grub entries generates, though - and would save you more support
questions ;-)

> and do everything manually by configuring your existing grub
> configuration accordingly. If the file system you have chosen for
> KNoppix is something that grub understands, you should be able to
> add the correct entries for kernel and initrd without installinf a
> partition bootloader. I think that Fabian just added the partition
> option in order to be able to boot Linux from a Windows "boot.ini"
> bootloader (or whatever this is called there).

Thanks a lot for the info. Knoppix really is an amazing bit of kit.
I'm actually testing it on a new laptop, which, it has turned out,
won't load a Debian 2.6 kernel without mods - 2.4 works okay, but is
u/s for a modern laptop - yet Knoppix only required acpi=off.


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