One of the biggest headaches in the Open Source world is the myriad of licenses available , many of which are incompatible with one another. These incompatibilities are troublesome enough between two separate projects, but when multiple licenses are used within the same software, the difficulties grow exponentially. Yesterday was a blow against multiplicity, as Sun decided to do something about it.

The Open Source Initiative lists no less than sixty five licenses certified as Open Source through the Initiative's license review process. These include the ubiquitous GPL and its family of variants, the Apache License, at least BSD licenses, the Mozilla Public License, the MIT license, and a host of lesser-known but nonetheless complicating licenses. The list does not, of course, list the wide range of licenses that have not been reviewed. Attempting to work one's way through them all requires a machete, Tenzing Norgay, and an advance reservation for a padded room.

One project with a proliferation of licenses — though thankfully compatible — is X.org. We count some seventy-six separate licenses in the xorg/xserver's COPYING file, most of which are derivatives of the "standard" license, itself an MIT license. Most derivatives bear roughly the same language along with a single distinguishing feature:

...and that the name of [the copyright holder] not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.

That file will soon have one less license, however, as Sun Microsystems' Alan Coopersmith announced yesterday that the company will begin licensing its contributions under the "standard" license, which does not bear the advertising/publicity provision. Further, Sun will re-license all of its prior contributions — some twenty-one years of substantial contribution — under the "standard" licenses, ridding the code entirely of its derivative license.

Coopersmith indicated that more than five hundred files will require editing. He noted, however, that contributors not affiliated with Sun should not change these notices, as the changelogs serve as an official record of the actions taken. In having specifically authorized Sun representatives make the changes, a paper trail of sorts is created, ensuring that any future issues regarding the licensing can be resolved quickly. He went on to say that if anyone has a pressing need for a particular file to be re-licensed posthaste, he can be contacted and will see that it is.