RE: 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.