[syslinux] can pxe localboot report failure to bios

Carl Karsten carl at personnelware.com
Thu May 19 10:33:30 PDT 2005

H. Peter Anvin wrote:
> Carl Karsten wrote:
>> <Docs>
>>     On PXELINUX, specifying "LOCALBOOT 0" instead of a "KERNEL" option 
>> means invoking this particular label will cause a local disk boot 
>> instead of booting a kernel.
>>     The argument 0 means perform a normal boot. The argument 4 will 
>> perform a local boot with the Universal Network Driver Interface 
>> (UNDI) driver still resident in memory. Finally, the argument 5 will 
>> perform a local boot with the entire PXE stack, including the UNDI 
>> driver, still resident in memory. All other values are undefined. If 
>> you don't know what the UNDI or PXE stacks are, don't worry -- you 
>> don't want them, just specify 0.
>>     On ISOLINUX, the "type" specifies the local drive number to boot 
>> from; 0x00 is the primary floppy drive and 0x80 is the primary hard 
>> drive. The special value -1 causes ISOLINUX to report failure to the 
>> BIOS, which, on recent BIOSes, should mean that the next boot device 
>> in the boot sequence should be activated.
>> </Docs>
>> I think I want the bios to figure out what to boot next, as if pxe had 
>> not happened.  What I get from the docs is when using pxelinux, I have 
>> to specify what device to boot.
> I'm not sure how you get that for the docs, unless you're reading the 
> paragraph which explicitly starts with "On ISOLINUX..."  You want 
> "localboot 0" for PXELINUX.
>     -hpa

I think it was the combination of "cause a local disk boot" and then later "On 
ISOLINUX, ... local drive number" that confused me.

Can you expand on "The argument 0 means perform a normal boot." - I am not sure 
what a normal boot is.  My first guess is reboot the box, and end up back in pxe boot.

I am being extra careful on this one because it is slated to be setup on Ubuntu 
Linux next release, so not only does it need to work on my few boxes, but also the 
few 100 others that go this route, including the 1 or 2 that do something nutty, 
like install on a USB drive.  (granted the 1 or 2 nutty ones are apt to be able to 
tune the config to make it work, but it would be nice if it "just worked (tm)." ;)

Carl K

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