> Well, I've got a question.  This has come up before, but I never
> understood the rationale.  Last time, I was told "NetBSD can't have
> GPL'd code" but nobody said why.
> 
> I'd like to know why.  It seems to me that the GPL guarantees that
> source code will always be available.  If NetBSD has this same
> philosphy, what's the problem?  If it doesn't, why not?  [Perhaps
> someone could post the NetBSD version of the GPL?  Then I could
> compare them myself...]

Here's an example copyright header (sys/kern/tty.c):
/*-
 * Copyright (c) 1982, 1986, 1990 The Regents of the University of California.
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *

So, the most important difference is that you can do "almost anything" with
the source as long as you give proper credit. Under GPL, you're *forced*
to disclose any sources you develop based on GPL sources, if you'd like
to distribute your product, possibly SELL your product. Introducing just
one GPL source into the kernel would *force* you to distribute source
to anything you develop on the kernel, even if you just plain include and
don't change that GPL source. The BSD sources have a very liberal copyright,
and I don't want to restrict them all of a sudden to GPL conditions.

Things look slightly different when talking about applications to go
into the system. They're closed "objects" by themselves. Using for example
gcc as the system compilier doesn't force you to also distribute sources
for your commercial application FOOBAR you'd like to distribute with
the system.

> Heck, if I knew that the NetBSD wasn't going to restrict the code
> somewhere down the line, maybe I'd finish the read/write stuff
> myself?  I've been thinking about trying out NetBSD...  ;-)

Grin, give it a try!

There could EVEN be an alternate solution to this problem! NetBSD knows
about loadable kernel modules (LKM). Implementing this filesystem as an LKM
file system, there wouldn't be a fixed link between the kernel and the
object files. Both, the kernel and the object files of the filesystem would
be distributable seperately. That way, I think, the filesystem code could
remain GPLd without making the kernel itself GPL. Well, I'm no laywer...

-Markus
-- 
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