Copyright, Copyleft and Copycentre

• We are used to seeing the following sort of copyright on commercial software:
  1. We own this software.
  2. We make no claim that it is suitable for your use, or even that it works.
  3. If you should suffer any damage in using this software, we will do the minimum required by law to help you.
  4. You can use this software, but you cannot redistribute it.

  Not very inspiring, huh?

• The Free Software Foundation, which produces much of the application software in FreeBSD, protects its software with the GNU ``copyleft'':
  1. Points 1-3 from the copyright above.
  2. Not only can you redistribute this software, but you are obliged to give someone a copy for free, if they ask.
  3. If you make any changes to this software, you must not claim to have written the original software, nor can you claim that we wrote your changes.
  4. You must place any changes you make to this software under this copyleft.

• Commercial developers have trouble with point 4, and often shy away from software protected by the GNU copyleft.
• This is a shame, as much of the GNU software is as good as, if not better than, equivalent commercial software.
• Following the tradition of the Berkeley Software Distributions, the FreeBSD project distributes its software either covered by the contributing author's copyright, or with a ``copycentre'':
  1. Points 1-3 from the copyright above.
  2. You can redistribute this software for free, or charge for it.
  3. If you make any changes to this software, you must not claim to have written the original software, nor can you claim that we wrote your changes.
  4. You can place any changes you make to this software under any copyright you like.
  5. You must acknowledge the use of this software in any product which uses it.
• This allows commercial organisations (e.g Novell, Sun, DEC etc.) to use copycentre'd code, possibly alter it (adding value), and sell it to you.
• The copycentre doesn't restrict your right to copy software for free, nor does it restrict your use of the software in a commercial product.