Re: grub2

[Andrei Borzenkov]

11.09.2015 16:25, Chopper пишет:
> Hi all,
> I have a few questions about diskboot.S.
> Here is the last few lines of this file:
>
>
> /* fill the first data listing with the default */
> blocklist_default_start:
>         /* this is the sector start parameter, in logical sectors from
>            the start of the disk, sector 0 */
>         .long 2, 0
> blocklist_default_len:
>         /* this is the number of sectors to read.  grub-mkimage
>            will fill this up */
>         .word 0
> blocklist_default_seg:
>         /* this is the segment of the starting address to load the data into */
>         .word (GRUB_BOOT_MACHINE_KERNEL_SEG + 0x20)
>
>
> firstlist:      /* this label has to be after the list data!!! */
>
>
>
> Question:
> 1.I want to know how the value of blocklist_default_len  is filled.

grub-mkimage. This is even written above in comments.

> 2.Is blocklist_default_len equal to the size of kernel.img?

No. core.img includes additional modules and usually is compressed. 
kernel.img is not enough to do anything useful.

> 3.Is it passible to get the size of kernel.img and use it as one of some 
> parameters to hash kernel.img in diskboot.S?

Not sure I understand the question. grub supports self-healing 
installation using reed-solomon encoding and is using it e.g. when 
installing in MBR. Is it what you ask?