[gPXE] Booting from dvd drive when sanboot fails

[Gene Cumm]

On Thu, Jan 13, 2011 at 00:26,  <olias at atlanticbb.net> wrote:
> Hello all,
>
> I'm trying to set things up so that gPXE or PXElinux will boot to the optical drive when sanboot fails so I can install an OS. I know this is supposed to work by default but my BIOS is junk. Yes, the dvd drive is set up to be the second boot device after the network card. I posted my question on linuxquestions.org so I wouldn't junk up your inboxes. The post is here: http://www.linuxquestions.org/questions/showthread.php?p=4222474
>
> And thank all involved for developing gPXE. It's great!

I just posted two replies at LinuxQuestions.org correcting the
SYSLINUX-related syntax errors.

As far as anything else, it'll depend on what "sanboot fails" results
in.  A permissive failure should tell the BIOS to use the next boot
device.

Have you tried to see about upgrading your BIOS?  I'm assuming the NIC
in question is a LoM (LAN On Motherboard) and probably gets its PXE
stack from the BIOS ROM.


If it's blank (binary 0's), all it'll do is execute the instruction
"add [bx+si],al" (if I have the info correctly). In order to do
anything useful, it needs to execute something like "INT 18h" or "INT
19h". Some BIOSs are nice and analyze the boot sector to determine if
it's a blank before executing it. I believe gPXE just boots it.

Manually booting from an optical drive probably won't work because
booting an optical drive normally requires the BIOS to configure the
El Torito boot. I'm very uncertain you'll ever find the answer you
seek.

-- 
-Gene