OpenSolaris

OpenSolaris is a completely free and open source version of the Solaris operating system. OpenSolaris is made up of source code for the commercial Solaris operating system and both products will feed each other. The two "versions" of the operating system are based on the same source code, with the major benefit for OpenSolaris users that they have access to the latest source code and bug fixes for Solaris. OpenSolaris is not, in any way, a cut-down or restricted version of the main Solaris operating system, it is just an open source version of that solution.

Sun has formalized the open source approach by making OpenSolaris available as a distribution in the form of the Solaris Express: Community Release, a free version of Solaris, based on the OpenSolaris code and designed to be used to help further develop the OpenSolaris product. The release is available as a set of CDs (four, currently) available for free download as ISOs which you can write and use to install Solaris. Both the SPARC and x86 versions are available and although the current Sun Download Center interface requires you to click for approval before download, technically the license does not require click-approval.

If you prefer, you can download the sources and build them for yourself to create your preferred Solaris operating system. The whole process can take from about an hour to 24 hours depending on your hardware and environment.