Re: Sun's ZFS and Linux

From: Rob Landley
Date: Mon Nov 21 2005 - 12:24:52 EST

On Sunday 20 November 2005 15:12, Tarkan Erimer wrote:
> Thanks for the explanation. BTW, I wonder something: Is there any
> possibility to give GPL an exception to include and/or link to CDDL
> code?

No, and Sun likes it that way.

The GPL was the first "copyleft" style license which requires that derivative
works be placed under exactly the same terms as the original work. If the
terms of another code are incompatible, they cannot be exactly the same.

(Specifically, the GPL says in section 2b, "You must cause any work that you
distribute or publish, that in whole or in part contains or is derived from
the Program or any part thereof, to be licensed as a whole at no charge to
all third parties under the terms of this License." See
""; and

Sun intentionally designed the CDDL to be incompatible with the GPL. This was
a design goal on Sun's part.* They want to isolate themselves from the
existing open source community, and make sure that their code cannot be used
with the most common open source license.** Why they want to do this has
been widely speculated about***, but the fact they want an explicit "us vs
them, no sharing" stance is not in dispute.


* See or
or plus Sun's official rationale

** According to
there are currently 72,823 projects on sourceforge specifying a license. Of
those, 48050 have chosen to license their code under the GPL. That's 65.98%,
or about 2/3 of the total. In politics, this would be flirting with a
veto-proof majority. David Wheeler did a detailed analysis at

*** see or or,1759,1754155,00.asp or,1895,1739000,00.asp or,289202,sid39_gci1060779,00.html
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