We first got a whiff of something brewing in the pipes last week when an email was sent to opensolaris-announce advertising the announcement of something called Illumos. Speculation ran rife about the possibility of what Illumos would be with many guessing it would be a fork of OpenSolaris or another OpenSolaris based distribution.
Well, last night we found out that it's neither. Illumos is in fact a "downstream" project to create a fully open-source-licensed, independently run version of the OpenSolaris operating system and networking consolidation (the OS/Net - aka ON - consolidation) code base (the closest OpenSolaris comes to a "kernel project") with the possibility of becoming a fork, if Oracle decides to pull the OpenSolaris code base. The idea behind the project is to run a child of the OpenSolaris OS/Net source that will track all the changes in its parent, maintain OpenSolaris ABI compatibility, but with the difference being that all the currently closed-source code will be replaced with open-source code and with the added opportunity for code submitted by external sources, and deprecated code, to be included and still available for others.
All changes and enhancements made in Illumos will be passed back to Oracle for integration into the OpenSolaris code base if Oracle so chooses to include them, keeping in mind some of the changes may not be consistent with Oracle's business needs.
At the moment the project is quite small with only 12 developers working on it, but they expect this to change quite rapidly. The project currently has backing from Nexenta (the tech lead - Garret D'Amore works for them), Joyent (who recently took on Bryan Cantrill), Greenviolet, EveryCity and several others with Nexenta and Joyant particularly enthusiastic - Nexenta plans on switching to Illumos for the base of their next release. Oracle has been approached, but has yet to respond.
All in all I think this is a great idea and a fantastic way to reawaken the community and excitement in OpenSolaris, and ideally with Oracle's involvement and input. It's understandable for Oracle to be quiet about the future of OpenSolaris as I suspect they're still trying to work out what path they want to take OpenSolaris and I suspect we may find out more at OpenWorld 2010 in September, but their involvement with Illumos would be great and would certainly help the evolution of OpenSolaris in the long run.