Re: Question about booting

["Martín Ferrari" <martin.ferrari@gmail.com>]

Hi,

On 8/8/07, Brad Boyer <flar@allandria.com> wrote:

> > - the /install folder is -hfs-blessed, but don't know what that means,
> > - there is another chrp descriptor called ofboot.b, but I don't know what it is,
> > - the yaboot boot loader is present, but I couldn't find what enables it,

> of the path is a special Mac shortcut that says to look for a
> particular file type (tbxi is a code for a bootloader). Older Mac ROM
> code was hard-coded to only look in the blessed folder for the System
> file.
>
> Because of this, booting from a blessed folder on a CD could use a
> boot path as simple as "cd:,\\:tbxi".

Ah, I see, so the mapfile does the magic here:

.b      Raw    'UNIX'   'tbxi'  "bootstrap"

So, this is neither prep nor chrp, yes?

> The ofboot.b file is a way to give boot options and configuration
> to Open Firmware. I haven't used it on a CHRP system, but on a Mac

>From what I've read in the CHRP paper, it looks for a file called
bootinfo.txt; it said nothing about other files...

> it allows you to set an icon for a drive and load a secondary
> bootloader. The ofboot.b file is generally given the HFS file
> type of tbxi to fit in with the default settings Apple sets. Here
> are the relevant files on a real install:

> The yaboot bootloader can be set directly in the firmware or it
> can be referenced from the ofboot.b file. My system has the following
> command set as one of the possibilities in ofboot.b:
>
> : bootyaboot " Loading second stage bootstrap..." .printf 100 ms load-base release-load-area " /ht@0,f2000000/pci@7/k2-sata-root@c/k2-sata@0/disk@0:2,\\yaboot" $boot ;

I see. But in the debian-cd's map, yaboot gets a filetype of boot
(just like in your setup). But you said that the firmware was looking
for tbxi...

> This is telling the firmware to create a command bootyaboot that will
> load and run the file yaboot in the blessed folder on the 2nd partition
> on the SATA disk. The ofboot.b file also has a menu to choose a boot
> method which can run this command based on the user input.

Yes, and it has the same format as bootinfo.txt, it confuses me completely :)

> With an Open Firmware that can directly load an ELF file, the yaboot
> file could be specified as the boot-file setting. This would mean
> that the firmware would always load yaboot as the normal boot process.

i see... So, the boot process you described would be:  firmware, if
used with boot "cd:,\\:tbxi", locates a blessed folder with a tbxi
file on it: the ofboot.b, which calls yaboot. Right? Do you know
anything about the remaining bits I've found?

Thanks a lot!


-- 
Martín Ferrari