I have a vague concept, but I would fail any test over the boot process. I’ve read a page about the grub2 commands but still am having a hard time understanding exactly how it works, or maybe what choices I need to make on the install.
To demonstrate my lack of understanding and question, after the first OpenSUSE version I installed, I now have created multiple partitions on my hard drive with a home partition separate. I installed 12.1 on an extended partition. Having read that not all computers support booting to extended partitions, I was prepared for it not working. When I restarted the system, it was just a blinking cursor. So I used a gparted disk to flag the original system, added to its menu to chainload to the extended partition and got the system to work.
With 12.3, I managed to get a primary partition available and installed it on that. However, booting still did not work. So now I don’t know if the extended partition might have booted if I understood what I needed to do.
Maybe since it is using grub2, it needed to change the main MBR of the whole hard disk?
Anyway, where I get confused is on the boot loader setting screen. On the 13.1 setup, I see the similar help screens which do not really tell me what I could understand.
There are several checkmarks, and could it be valid to check multiple ones, or only one?
When it says, boot from Master Boot Record, does that mean it will change my whole hard drive boot process and if something was working it may no longer work?
When it says Boot from Root Partition, is that … Well, I don’t know what that could mean… Is root same as boot? For those having a separate boot partition from your main system play a role here? Since there’s a checkmark for extended, does root mean like primary? Is root whichever partition your main system (/) is on so it really means set a flag? But then on the Boot Loader Options Screen there’s something for setting active flag, so I don’t know what this means here. There’s also something about writing code to the MBR. I may have done that back at 11.2 or whenever, but I originally was trying to install windows 98 without luck with new hardware (or maybe something with the booting process?).
When it says Boot from Extended Partition, how does that relate to the options screen about setting a flag?
I don’t want to change my main disk MBR or whatever it’s called. I may want to or have to if grub2 requires it, (and in the future), but I want to know what would impact that. Changing my target extended partition I don’t care about if that’s all it changes. Is there a boot record for the partition that maybe I’m not allowing to be written on install?
What impact does checking or not checking the various options have and when would, why would I check them?
The help screen says “Write Generic Boot Code to MBR in Boot Loader Options to update the master boot record if that is needed”. Do I need it? When do I need it? I’m thinking if I had windows running in a partition I would never write to MBR. I am assuming the MBR is for the whole hard disk and enables booting to whichever partition is flagged for booting.
I just know enough to know I don’t know much. Mainly I want to know which check marks to check and why and when and what it does where.