Colin Wood wrote:

<snip>

> So, you basically cannot use Linux kernel source
> code in a NetBSD kernel or vice-versa.  For the mac68k ports of Linux and
> NetBSD, this means that each camp must figure out all the hardware for
> themselves, duplicating a lot of effort in some cases.  Of course, some
> sufficiently kind kernel hacker could fully document the hardware outside of
> the source code, but that almost never happens ;-)
> 
> I hope this explains it a little.
> 
> Later.

This  is my first thought on this, and I might change my mind after
thinking about it some more, but I disagree in part.

Say for example that some Linux code, possibly a header file had
information about a bunch of registers that you needed to make some
hardware work. You can take the information, the location of the
registers, and anything else factual, from the Linux code and use them
to write NetBSD code without infringing the copyright on the Linux code,
as long as you don't take anything expressive, which would include
comments in most cases, and any actual code that was present (although
you can take the ideas included in the code). 

What is sometimes done, is one person looks at the copyrighted code, and
writes a spec that includes all the factual stuff, but none of the
copyrightable expression (the actual code), and another person who
hasn't seen the original code uses the spec to write functionally
equivalent code, which does not infringe, even if it turns out to be
very similar, or even identical. This is because identity isn't enough
for there to be copyright infringement, there has to be copying. The
presence of a lot of identical code is evidence of copying, because
coincidence only goes so far, but it is only a rebuttable presumption.
If you can prove independant creation, there is no copyright
infringement.

The leading case on this involved copying a telephone directory. The US
Supreme Court decided that the information (names, addresses and phone
numbers) in a telephone directory could be copied without infringing,
even though it took a lot of work to assemble it. They said that these
were pure factual things, not subject to copyright. They threw out the
so called sweat of the brow test which previously had given protection
to things that took a lot of work to assemble. 

Since Colin does this for a living I expect he knows all of this, (the
reference to the mythical kind kernal hacker (KKH) writing the spec is
what I was talking about)  but I wanted to clarify a little. The KKH can
use the Linux code to document the hardware, it doesn't have to be the
person who wrote the code who does it.

Brad



Brad Salai			bsalai@tmonline.com
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