GPL vs BSD Licence

[David Schwartz]

>   But then, I'm not sure (and I mean it) if there can be any piece of
> software which, if designed for e.g. Linux, can be written w/o using any
> system headers, libraries or whatsoever.

	You can do this with only moderate difficulty and moderate inefficiency if
you want to. All you have to do is:

	1) Define your own kernel interface that your proprietary module will use.

	2) Implement this interface in a kernel module that is GPL.

	3) Distribute your proprietary module such that it uses only your own
interface.

	This way, your module need only use your own headers, which you distribute
under the GPL as well as other licenses.

	The inefficiency comes from having to convert between your own structures
and values to and from the Linux kernel structures and values. If you're
really clever, you can rig it so that the conversion reduces to no-ops on at
least some kernel versions for many conversions, still without using the
Linux kernel header files.

	You are also free to use subterfuge of any kind to get around any
restrictions the Linux kernel may attempt to impose upon you because these
are not license enforcement mechanisms. The Linux kernel does not, and *may*
not, contain any license enforcement mechanisms that affect *use*, and
obviously anything that could affect the runnning of your module would be
affecting use. (The GPL does not restrict use and prohibits any 'additional
restrictions', thus any thing that seemed to be an additional restriction
could not be a license enforment mechanism because the restriction is not in
the license.)

	DS