Booting from USB flash drives

[Brian D]

Actually it is possible to put the modules on the boot
sector in a compressed file that the bootstrap precess
uses. Secondly grub and lilo for that matter doen't
need the BIOS to detect hardware and in fact I do not
beleive either process uses the BIOS, but directly
calls the hardware bypassing the BIOS. That is a
common misconception that one can only use the BIOS.
The BIOS is nothing more than a software program
burned into a chip. It is true that the BIOS will look
where ever it is told to look to find the bootstrap
program and that the bootstrap program needs to know
how to handle any device that isn't known to the BIOS.
So after talking it out in my head, the bootstrap
program has to know how to access USB if the BIOS
doesn't. So it is 'BK' - 'Before Kernel'. So it is
irrelevant to whether or not you make the kernel aware
of USB. So I guess I was initially wrong in my
thinking. So I guess I'll start looking at grub's
source code and the USB module code and see if I can
find a way to make a 'USB aware' grub for those of us
'poor masses' who can't select a USB device from the
BIOS. I'll have to look at mine. I have some unusual
choices if I remember correctly, including one entry
for "other boot device". And I know that writing my
own BIOS is out of the scope of the original post.

Regards,
Brian
--- Jonathan Hutchins <hutchins at tarcanfel.org> wrote:
> If I understand the process correctly, you can't
> really boot from a divice 
> that isn't supported by the kernel itself - deviced
> supported through modules 
> aren't bootable, because the kernel has to have the
> filesystem open to read 
> the modules.  Therefore you'd have to compile the
> USB and USB/Filesystem 
> modules into the kernel for it to be bootable.
> 
> As far as getting grub or lilo to read a USB device
> for the boot source, I'm 
> not sure that that would work unless, as has been
> suggested, the MB's BIOS 
> offered USB as a bootable device.
> 
> Hacking ROMs and other devices is really beyond the
> scope of the original 
> question.
> 
> 
> majordomo at kclug.org
> Enter without the quotes in body of message

__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com