[Discuss] ZFS

[Edward Ned Harvey]

> From: discuss-bounces+blu=nedharvey.com at blu.org [mailto:discuss-
> bounces+blu=nedharvey.com at blu.org] On Behalf Of
> 
> ZFS was released under the CDDL license, which is open source but grants
> the owner to close source the software.  That's what Oracle did with
> Solaris, 

No matter who you are, no matter what open source license you release
something under, if you are the copyright holder, you have the right to
re-release your code under any new license you want, and you have the right
to stop releasing future developments.  (Make it close-source.)  The same
does not apply to non-copyright holders, because the only rights the
non-copyright holders have are those rights granted to them by the copyright
holders.  And the terms under which the copyright holders released the code
required the recipient to preserve these license terms for all their new
developments.  (Copyleft.)  No matter who you are and no matter what license
you use, you cannot revoke any of the rights you've already granted on
previously released code.

In a former life, at a software company, we found a GPL open source library
that would be really useful in our closed-source commercial product.  Our
company negotiated license terms with them, and paid for that code to be
licensed to us under different terms, which would allow us to build it into
the commercial product.

(Side note)  GNU endorses the GPL instead of the LGPL, because the LGPL will
allow commercial entities to build your LGPL code into their commercial
product, and sell it inside their closed-source proprietary product, without
paying you anything.  If the aforementioned library had been LGPL, we could
have put it into our product for free.


> but there is no ground for infringement suits, because everything
> released as open source remains in the community.

Sorry, that's incorrect.  If somebody patents something, and later somebody
else releases an open-source thing which violates that patent, then the
patent holder has grounds for legal action, against the producers,
distributors, and users of the thing.  Typically they'll just go after the
producers and distributors.


> The ability to close source it is, I believe, what makes it incompatible
> with GPL.

Nope.  The reason it's incompatible is like this:  In the GPL, a "covered
work" is anything which is derived from the GPL licensed source.  So the
binaries compiled from the source are also GPL.  If somebody writes a
library under GPL, and somebody else builds a binary with that library
statically linked into it...  The GPL compiled code was therefore included
in the second guy's binary file, and hence the second guy's binary must also
be GPL, which means the second guy's source must also be GPL.  Which means
anything in the world based on the second guy's source must also be GPL.
This is a very strong copyleft statement.

In CDDL, only the source code and modifications to the source code are
covered by the CDDL.  Binaries may be distributed separately and under a
separate license, including components that may be closed-source.  So
imagine if you linked ZFS into the linux kernel.  Then the ZFS code must be
GPL compatible, and anything else in the world based on ZFS must be GPL
compatible...  Which it's not.  For example, the solaris kernel.

You can actually download the ZFS and Linux source code yourself, compile it
yourself, use it yourself, no problem.  But when you distribute the
resultant product, you must give the license terms to the recipient...  And
there is no conglomerate fusion of GPL/CDDL license terms you can grant
recipients to satisfy the requirements of both.  So in other words, you
can't distribute it.


> I have used Solaris 11 Express to build a few storage devices for NFS,
> CIFS and iSCSI sharing with very positive results, so you don't have to go
> with a fork to use ZFS.

Well, that's not actually allowed.  Sol11Exp is only free for development
purposes, and some other purposes as outlined in its EULA.  Not permitted to
be put into a production fileserver/storage server for free.  The last such
release was solaris 10u8, or genunix opensolaris b134, or the
openindiana/illumos fork which is based on the above.