A Sun engineer heading the effort to open source Solaris has published a new software licence that could be used for its open-source release.

Sun is being vague on actual details, although the Common Development and Distribution Licence (CDDL), will not be compatible with Linux's software licence.

The CDDL was submitted to the Open Source Initiative (OSI) on Wednesday by Claire Giordano, an engineering manager with Sun. But she wrote at the same time that it is "not expected to be compatible with the GPL". GPL is the GNU General Public Licence - the open-source licence used by Linux.

Sun spokesman Russ Castronovo declined to comment on Sun's plans and would not say whether it would be used with Solaris or some other open source project. He described the submission as "just part of our ongoing efforts" in the open source community. "We're not attaching this to any product, nor are we saying it's not going to be part of any product," he said.

One open source advocate saw Sun's reluctance to explain the licence as part of a broader strategy. "Sun obviously would like to keep people confused as much as possible, because their main purpose here is to slow down the Linux market by making purchasers for x86 systems delay," said Bruce Perens, a founder of the OSI who is no longer on the initiative board.

If the licence is adopted for Solaris, it will prevent Sun's operating system from being able to use the many free device drivers that have already been written for Linux and licensed under the GPL, he said. "It will be an open source piece of code that can't stand on its own, that requires non-free device drivers to operate," he said.

Castronovo dismissed the idea that Sun was looking to harm Linux. "People ascribe all sorts of nefarious intents to Sun," he said. "What they really need to do is focus on what's going on with the licence. Do you think Sun could really slow down the Linux marketplace at this point in time?" he asked.

Sun's new licence is very similar to the Mozilla Public Licence, created by Netscape for its open-source browser project, but it removes a number of idiosyncrasies, including a requirement that the licence be governed by California law, Castronovo said. "It was clearly a good licence, we just cleaned up a few things that we thought needed to be cleaned up," he said.

Earlier this year, Sun announced plans to release an open source version of Solaris by year's end, but the company has been quiet on specifics. In addition to leaving the licensing question unanswered, the company has not said exactly what parts of Solaris will be released or how the open source code will be managed.