The previous
software license used by
Sun for its
open source projects was the
Sun Public License (SPL), also derived from the
Mozilla Public License. The CDDL license is considered by
Sun (now
Oracle) to be
SPL version 2. The CDDL was developed by a
Sun Microsystems team (among them
Solaris kernel engineer Andrew Tucker and Claire Giordano), based on the
MPL version 1.1. On December 1, 2004 the CDDL was submitted for approval to the
Open Source Initiative While the
Free Software Foundation (FSF) also considered the CDDL a
free software license, they saw some
incompatibilities with their
GNU General Public License (GPL). For instance, the FSF considered the CDDL incompatible to their GPL license, without going into detail until 2016. CDDL is one of several
Open Source Licenses which are
incompatible with GPL. This characteristic was inherited from the MPL 1.1 (fixed with the MPL 2.0 according to the FSF the root of the problem being GPL
virality, similar to other cases of GPL incompatibility. Some people argue that Sun (or the Sun engineer) as creator of the license made the CDDL intentionally GPL incompatible.
Simon Phipps (Sun's Chief Open Source Officer at the time), who had introduced Cooper as "the one who actually wrote the CDDL", did not immediately comment, but later in the same video, he says, referring back to the license issue, "I actually disagree with Danese to some degree", while describing the strong preference among the engineers who wrote the code for a BSD-like license, which was in conflict with Sun's preference for something
copyleft, and that waiting for legal clearance to release some parts of the code under the then unreleased GNU GPL v3 would have taken several years, and would probably also have involved mass resignations from engineers (unhappy with either the delay, the GPL, or both—this is not clear from the video). Later, in September 2006, Phipps rejected Cooper's assertion in even stronger terms. Similarly,
Bryan Cantrill, who was at Sun at that time and involved in the release of CDDL licensed software stated in 2015 that he and his colleagues expected in 2006 the fast emergence of CDDL licensed software into the Linux ecosystem and the CDDL being not an obstacle.
cdrtools controversy The GPL compatibility question was also the source of a controversy behind a partial relicensing of
cdrtools to the CDDL which had been previously all GPL. In 2006, the
Debian project declared the cdrtools legally undistributable because the
build system was licensed under the CDDL. The author,
Jörg Schilling, claimed that
smake is an independent project and does not violate the
GPLv3. Schilling also argued that even though the GPL requires all scripts required to build the work to be licensed freely, they do not necessarily have to be under the GPL. Thus not causing an incompatibility that
violates the license. He also argued that in "combined works" (in contrast to "
derived works") GPL and CDDL licensed code is compatible.
Red Hat's attorneys have prevented cdrtools from being in
Fedora or
Red Hat Enterprise Linux, arguing that Schilling has an "unorthodox" view of copyright law that isn't shared by their legal counsel or the Free Software Foundation.
ZFS in the Linux kernel In 2015, the CDDL to GPL compatibility question reemerged when
Ubuntu announced inclusion of
OpenZFS by default. In 2016 Ubuntu announced that a legal review resulted in the conclusion that it is legally acceptable to use ZFS as binary
kernel module in Linux. (As opposed to building it into the kernel image itself.) Others followed Ubuntu's conclusion, for instance James E. J. Bottomley argued there cannot be "a convincing theory of harm" developed, making it impossible to bring the case to court.
Eben Moglen, co-author of the
GPLv3 and founder of the
SFLC, argued that while the letter of the GPL might be violated, the spirit of both licenses is unharmed, which would be the relevant aspect in court. The SFLC mentioned also that a precedent exists with the
Andrew File System's kernel module, which is not considered a derivative work of the kernel by the kernel developers. On the other hand,
Bradley M. Kuhn and attorney
Karen M. Sandler from the
Software Freedom Conservancy argued that Ubuntu would violate both licenses, as a binary ZFS module would be a derivative work of the kernel. In April 2016, the
Ubuntu 16.04
LTS release included the CDDL-licensed
ZFS on Linux. ==Adoption==