Le 06/08/2016 à 16:18, Felix Miata a écrit :
Pascal Hambourg composed on 2016-08-06 12:01 (UTC+0200):
...
If the boot image is in a PBR, the BIOS won't load it directly
It will if the PBR is on a primary partition on the same disk.
On the same disk as what ?
Do you mean that the BIOS can load directly the boot sector of a primary
partition instead of the MBR ?
It's how
all my systems boot if I'm not using IBM Boot Manager as the primary
bootloader.
What do you call "IBM Boot Manager" ? Is it the boot manager used by
OS/2, or the generic/legacy boot code in the MBR used by MSDOS and
Windows, which loads the PBR of the primary partition with the boot flag ?
Also, what does your MBR contains ? Only the partition table, no boot
code at all ?
After reading your reply I made a quick test on three different PCs.
I installed a generic MBR boot code on a USB stick and checked that it
could boot on each PC and load the PBR of the primary partition with the
boot flag.
Then I erased the boot code (first 440 bytes in the MBR) with zeroes and
observed that the boot hanged on all my test PCs, so I concluded that
the BIOS still tried to load and execute the MBR because of the boot
signature at the end of the MBR. Then I also removed the boot signature
in the MBR and observed that the BIOS said the device was not bootable,
as expected.
