For some reason I never asked this before… when installing openSUSE there are checkboxes next to the various bootloader installation options (MBR, partitions, etc.) - now I realize I can check them all. This seems like it would be useful if it means what I think it means - and that’s my question - does it mean openSUSE can boot from any of those options? For instance, if I later install Windows, I can tell the Windows bootloader to boot openSUSE from it’s own root partition. (or from the extended partition?) Lately, when I install, I check several of them (except custom boot partition).
It means that – sort of.
There are two parts of installing grub. There is the location where the grub code goes, and there is the location of the boot sector that is use.
If one of your options is to install in the MBR, then part of the grub code will go in the unassigned disk space immediately following the MBR. Otherwise the grub code will go elsewhere, with a block list (list of disk blocks) used in the boot sector to find where it is installed.
If you include the MBR in your selection, and you later install Windows which wipes out the MBR, I would not bet on one of the other grub options still working. However, if you install on both the root partition and the extended partition, and if Windows wipes out what you did to the extended partition, you can get that back from using the root partition.
It means that openSUSE will perform bootloader installation on all of these options. The end result is likely highly bootloader-dependent. For LILO you cannot have multiple locations anyway. For grub2 this will likely result in subtly broken configuration - all bootloader locations except the last one will refer to deleted files, which means they stop working as soon as deleted location is overwritten. Thinking about it, it may be one reason of those mysterious “my system does not boot after update” cases … I’m not sure what grub legacy does in this case.
On 2013-09-08 06:46, arvidjaar wrote:
> working as soon as deleted location is overwritten. Thinking about it,
> it may be one reason of those mysterious “my system does not boot after
> update” cases … I’m not sure what grub legacy does in this case.
Grub1?
Mmm… boot sector code can be placed anywhere, or several places - as
long as they all point to the same, hardcoded, second level boot code
(not the correct name, I know), all would work.
–
Cheers / Saludos,
Carlos E. R.
(from 12.3 x86_64 “Dartmouth” at Telcontar)