Sun open source license could mean Solaris-Linux barrier

But the license may inhibit cross-pollination between Solaris and Linux--a sacrifice Sun appears willing to make in its effort to attract developers and revitalise its version of Unix.

On Wednesday evening in the US, Sun submitted a description of its Common Development and Distribution License, or CDDL, to the Open Source Initiative. The nonprofit group reviews licenses and bestows official open-source status on those that meet the Open Source Definition requirements.

The CDDL lets programmers see, change and distribute source code for any programming project it governs. Unlike some open-source licenses, it requires that modifications be shared as open-source software.

Sun hopes its open-source move will attract developers to Solaris and reinvigorate the operating system. Solaris waned in popularity with the Internet bubble burst and with the rise of Linux, which works better on widely used servers based on x86 processors such as Intel's Xeon.

But if Sun chooses to release Solaris under the CDDL--and it hasn't committed to doing so--the choice likely will prevent direct cross-pollination between the Unix variant and its prime competitor, Linux. That sharing is one of the prime advantages of the open-source philosophy; making Solaris open-source raised the possibility that it could benefit from Linux features such as widespread hardware support, and Linux could gain from Solaris features such as multiprocessor abilities.

Sun's CDDL description addressed the difficulties of intermingling software covered by the CDDL with software covered by the General Public License, or GPL--the license that governs Linux.

"The CDDL is not expected to be compatible with the GPL, since it contains requirements that are not in the GPL," Claire Giordano of Sun's CDDL team said in its submission. "Thus, it is likely that files released under the CDDL will not be able to be combined with files released under the GPL to create a larger program."

Open Source Initiative President Eric Raymond declined to comment yet on whether the license meets those criteria. But if the Open Source Initiative approves the license, the CDDL will join a list that already includes dozens of licenses.

This proliferation of open-source licenses is a problem, said Larry Rosen, an intellectual-property attorney who has advised OSI and who wrote "Open Source Licensing: Software Freedom and Intellectual Property Law."

"What we end with up is...lots of little lumps of software that can't be combined," Rosen said in an interview. "It is, in fact, a problem creating a commons of software if every company has its own commons."

Sun wouldn't comment on whether Solaris 10 will be covered by the CDDL. "We're not drawing linkage between that and any of Sun's products," spokesman Russ Castronovo said.

However, executives have said Sun will seek the blessing of the Open Source Initiative for the license, and the clock is ticking. Sun had wanted to make Solaris open-source by the end of 2004, though the company this month gave itself scheduling leeway until Jan. 17.

In its description, Sun said it tried to find an existing open-source license but "reluctantly" drafted its own when none of the others met its needs. However, Sun didn't start from scratch: The CDDL is a variant of the Mozilla Public License 1.1, the license that governs the Web browser project that helped bring the open-source movement to prominence in 1998.

Licenses can be filled with obtuse legal jargon, and at 2,744 words long, the CDDL isn't a light read for programmers thinking of throwing their hat into the ring.

Sun, though, believes its license is an improvement over existing open-source licenses: "We wished to create a license that was simpler, less burdensome for contributors, clear and consistent in the use of terms and language, and that was as reusable and general as possible," Sun said in a description of the license.

However, one significant figure in the open-source licensing realm received the license coolly: Mitchell Baker, an attorney and the author of the Mozilla Public License.

Part of Sun's agenda has been to have its license replace the MPL, Baker said in a Thursday posting to a mailing list on the Open Source Initiative's Web site. "I've looked at this license and think there are some ways that it simplifies things, but there may also be such other issues with this language that may come up in use. Why the big rush?" Baker asked.