Sorry. You clearly pointed out the answer, yet I failed to do as you instructed, next time I'll listen better.

Which do I put my loader in if I'm going to chainload from GRUB?

i think the same as withou grub. the boot record (not master boot record) of the partition where your loader is.

MBR>GRUB>part table> ext part table> your part > loader

So my loader should go in the boot record containing the extended partition table(the sector it took me forever to find)?

no
it should be in the boot sector that is pointed to by the extended partition table.

then, it is like a 4 or 5th addressing level.

in simplified x86 ram style:


of course, this is completelly false code, but the idea is there.

the MBR boots on grub
grud analyse partition table in MBR
it will analyse the partition table of part1 (hte one who don't have boot code (0)
it will find the ext1 prtition
and the ext1 partition will contain itself the id for its size, relative LBA will be 0

at this step, there will not be infinite boot nesting. the ext1 partition will not say to go to another partition, it will just say (as it is not the MBR) i am the valid partition.
this sort of strange design forced me to completelly ignore partition table and design my own partition table, and no matters if it don't work on PC others than mine.


it is easy to understand, but hard to explain without a drawing.

I'm sorry edfed and ManOfSteel, but I still don't get it. It's definitely not your explanation's fault, it's my being dumb. One more time, is it the Volume Boot Record or the Extended Boot Record that gets loaded it memory? I promise I'll never ask again. If I don't understand this time, I'll do like I should have a long time ago and quit osdeving.

btw, you should update your drawings thread, sure you've done some more awesome drawings since then.

Both are loaded at one time or another but for different purposes.

The entire chain of the EBR is read by operating systems and boot managers that bother to understand extended/logical partitions, so that they can display the different partitions on the disk, give the user access to the files stored there, and possibly load an operating system stored on one of them.

The appropriate VBR may then be loaded so that the corresponding operating system starts running, since the VBR contains the bootloader for that operating system. This is only done if a boot manager is involved.

So again, have you tried dding the LBA location I mentioned earlier (0x3de1783) and moving through the EBR from there by following zhak's process?

THANK YOU!!! I understand now.


Yeah, I finally got it after stupidly ignoring you telling me to repeat zhak(the first time) and then finding ~10 posts later that you had spoon fed the answer to me, but I hadn't listened. After finally getting the concept of a VBR and an EBR and their relation, I came to the question of which sector(EBR or VBR) gets executed as the bootloader. You just answered that, and again, thanks to you, edfed, and zhak.

i thuink that if you don't practice it, you will not understand it.
then, the better way to learn is to do.

please, reporting your experiments results. thanks.