Syslinux - Feb 2005 - Maximum line length of APPEND option in PXELINUX

Hi,

I just replaced the pxelinux.0 of some 2.x version by pxelinux.0 vers. 3.0.7.

Some of the PXE Clients refused to boot thereafter (just stopped after reading
the config file). I noticed that the APPEND line was too long.

Is this intentional? What is the maximum length of the APPEND option line?

Thanks, Thomas

Gebhardt Thomas wrote:
> Hi,
> 
> I just replaced the pxelinux.0 of some 2.x version by pxelinux.0 vers.
3.0.7.
> 
> Some of the PXE Clients refused to boot thereafter (just stopped after
reading
> the config file). I noticed that the APPEND line was too long.
> 
> Is this intentional? What is the maximum length of the APPEND option line?
> 
255 characters.

	-hpa

On Wednesday 23 February 2005 19:52, you wrote:

Hi,
> > Is this intentional? What is the maximum length of the APPEND option
> > line?
>
> 255 characters.
Thank you very much for the quick answer!

I can live with that. Just got surprised by the fact that my old pxelinux.0
(vers 2.11?) worked while the new one (vers. 3.0.7) just hangs without
an error message.

The long kernel command line originate from the Knoppix Linux Live CD
(or derived distributions) that (mis?)uses the kernel command line for
system configuration options ("cheat codes"). There is even a Knoppix
2.4 kernel patch that expands the maximum length of the kernel command
line.

Since Knoppix is rather widespread, the problem with the overly large APPEND
line might show up frequently when syslinux 3.x is adopted (Knoppix now uses
syslinux 2.x).

Cheers, Thomas

Gebhardt Thomas wrote:
> On Wednesday 23 February 2005 19:52, you wrote:
>>>Is this intentional? What is the maximum length of the APPEND option
>>>line?
>>
>>255 characters.
> The long kernel command line originate from the Knoppix Linux Live CD
> (or derived distributions) that (mis?)uses the kernel command line for
> system configuration options ("cheat codes"). There is even a
Knoppix
> 2.4 kernel patch that expands the maximum length of the kernel command
> line.
> 
> Since Knoppix is rather widespread, the problem with the overly large
APPEND
> line might show up frequently when syslinux 3.x is adopted (Knoppix now
uses
> syslinux 2.x).
The LEAF (LRP-based) distributions also tend to have long APPEND lines. 
  This will have to be watched for.

-- 
David Douthitt
UNIX System Administrator
Linux+, LPIC-1, RHCE
HP-UX, Unixware, Linux, FreeBSD, OpenBSD
Member: ACM, USENIX/SAGE

David Douthitt wrote:
> 
> The LEAF (LRP-based) distributions also tend to have long APPEND lines. 
>  This will have to be watched for.
> 
It probably should be pointed out that this is broken on earlier 
versions of syslinux too.  Just instead of a nice error message it 
overwrites random parts of memory.
	
	-hpa