Solaris 10, the official stable version of Sun's UNIX operating system, is no longer available to users at no cost. Oracle has adjusted the terms of the license, which now requires users to purchase a service contract in order to use the software.

Sun's policy was that anyone could use Solaris 10 for free without official support. Users could get a license entitling them to perpetual commercial use by filling out a simple survey and giving their e-mail address to Sun. Oracle is discontinuing this practice, and is repositioning the free version as a limited-duration trial.

"Your right to use Solaris acquired as a download is limited to a trial of 90 days, unless you acquire a service contract for the downloaded Software," the new license says.

It's important to understand that this change will not affect OpenSolaris, which is still freely available under the terms of Sun's open source Common Development and Distribution License (CDDL). Users who don't want to pay for service contracts will be able to use OpenSolaris instead. That might not be particularly comforting to some users, however, because there are is some uncertainty about the future of OpenSolaris.

Although Oracle has committed to continuing OpenSolaris development, the company says that OpenSolaris might not get all of the new features that are being developed for the Solaris platform. Oracle says that it is reevaluating some aspects of the development process and isn't entirely sure how it will proceed.

It's not clear exactly how this will play out, but it seems that Oracle might choose not to open the source code of certain improvements in order to differentiate its commercial Solaris offerings. If Oracle decides to move in that direction, then OpenSolaris will no longer be able to serve as a drop-in free replacement for the latest commercial version of the operating system.

OpenSolaris contributor Ben Rockwood, a Sun Community Champion, discussed the licensing change in a recent blog entry. The licensing changes will be detrimental to smaller Solaris users, he says. He also expresses some concerns about the future of OpenSolaris due to the lack of communication from Oracle about the current status of the overdue OpenSolaris 2010.03 release.

"There may be attractive offerings for new customers in the high-end enterprise space, but long time supporters in smaller shops are going to get royally screwed," he wrote. "This might be a good time to catch up on non-Sun/Oracle distros such as Nexenta, Schillix, and Belenix."

Sun started giving away Solaris for free so that it could retain mindshare for the platform as Linux gained a broader presence. Oracle doesn't really need to do that because it has robust commercial offerings for both Linux and Solaris. Oracle can afford for Solaris to become the niche premium offering while Linux dominates most of the rest of the market. If dropping the free version gets some existing users to start paying for service contracts, than it's a win for Oracle. The downside is that the changes in licensing will exacerbate the growing rift between Oracle and the existing community of OpenSolaris enthusiasts.