On 2016-02-02 18:51, Andrei Borzenkov wrote:
02.02.2016 18:36, Carlos E. R. пишет:
I used "Boot Info Script 0.72" (https://github.com/arvidjaar/bootinfoscript/raw/master/bootinfoscript) to obtain information on the boot process.
Could you send me privately RESULTS.txt and GPT table (first 32K of disk)?
Sure, thanks :-)
Now, what I don't understand is, how is BIOS booting this disk. Obviously it has to read the MBR, and this boots sda2. How does it know it has to boot this partition?
If "it" means BIOS, it does not know anything. It loads the first sector and jumps to it.
Well, no, I meant the machine, the computer, the system, all :-) At the time I wrote the question I had little idea who did the choice. The thing is, fdisk does not display by default the flags of the GPT partition; thus I did not see the "legacy BIOS bootable", but "parted /dev/sda print" displays that info.
Notice that there is no partition marked as boot, and that there is a "BIOS boot" partition, very small.
This is irrelevant in your case but may help if you decide to install GRUB2 in MBR.
No, I don't think I will do that. I prefer to leave Syslinux there. Changing which partition has the "legacy BIOS bootable", I can change which system boots, very easy. Then if grub is in a partition, it does not need a corresponding "BIOS boot". Good. I was starting to have nightmares caused by installing a dozen systems, each with its own "BIOS boot" partition, LOL!
P.S. of course not every BIOS is equal and there are known cases when BIOS won't jump to boot code unless it sees legacy MBR active partition. And of course there are firmwares that go amok when they see PMBR with Active flag ...
Argh. This test has been done with vmware player, so it is whatever BIOS vmware emulates. One day, soon I hope, I will attempt to boot the host computer with that hard disk. I hope it responds well, because it is real BIOS, not UEFI (made more than six years ago). If it doesn't, I will have to reformat the disk with traditional partition table. -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" at Telcontar)