Converting/Splitting Code - Open to Closed

[Dave J Woolley]

> This is one of the dangers of basing Linux (or any other large,
> multicontributor project) on the GPL; the threat that something embedded
> deeply in the code could eventually have an external patent applied,
> 
	[DJW:]  In the UK, one is always told never to reveal
	anything about something you intend to patent, except
	under a confidentiality agreement, because the patent 
	would be invalid if details were published first.

	Is this not true for US software patents?

	I'm pretty sure that no-one else could validly patent
	something that appeared in open source code, after the
	publication, as there would clearly be prior art.

	The real risk is that someone interprets an old patent
	of theirs as applying to code written after the patent
	was granted.

	I believe Netscape patentented SSL in order to reduce the
	risk of anyone else claiming that a patent applied.

	On the original question, I'm not sure about taking GPLed
	code out of GPL retrospectively, although I don't think
	the FSF intended this to be possible.  However, the
	copyright owner can licence the same code under a
	different licence and can licence a derivative that they
	themselves create under any licence they like.

	I Am Not A Lawyer.