YDL4.0: Multiple versions of kernel header files

[Joseph E. Sacco, Ph.D.]

I was wondering...

The file, 

	/usr/include/linux/version.h 

indicates that the set of header files found under 

	/usr/include/linux 

are from version 2.4.20. It would also appear that the header files
found under

	/usr/include/asm-ppc
and
	/usr/include/asm-ppc64

are also from 2.4.20.


/lib/modules/2.6.x/build is no longer a link to the source tree but
actually contains directories like "include".

The file,

	/lib/modules/2.6.x/build/include/linux/version.h

indicates that the set of header files under

 	/lib/modules/2.6.x/build/include/linux

are from version 2.6.x.


Questions:
----------
* Why are there two different sets of kernel header files installed
under YDL-4.0?
  
* What happens when you build something that uses kernel headers?

* What happens when you run something built with the 2.4.x headers on a
system running a 2.6.x kernel?

* Which set was used when building the YDL-4.0 packages?

Observation:
------------
The sheep driver for MOL will not build using the 2.6.x headers. There
has been a change in the definition of the structure sk_buff as can be
seen from examining skbuff.h. I sent Samuel email.

-Joseph

-- 
Joseph E. Sacco, Ph.D. <joseph_sacco at comcast.net>