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What is the objective of the illumos project?

illumos is a fully open community project to develop a reliable and scalable operating system. It began as a fork of the former OpenSolaris operating system.

Our goal is to foster open development of technologies for the 21st century while building on a twenty-year heritage, but free from the oversight of a single corporate entity and the resulting challenges thereof.

While our code base has a long history and many engineering traditions attached to it, our development processes are being reinvented in an attempt to remove barriers while maintaining consistently high code quality.

How do I download the software?

The source code developed by the project is a fork of the Sun/Oracle code base referred to as "OS/Net" or "ON" (short for Operating System/Networking). It is the home of the technologies that previously defined OpenSolaris and Solaris, such as the kernel, network stack, filesystems, and device drivers, and all of the basic userland libraries and applications.

The illumos code base forms the foundation of distributions. To use the operating system, just download and install one of the distributions.

To download the source code, review Building illumos. You can also browse on GitHub or search on OpenGrok.

Is illumos free software (open source)?

The bulk of the illumos source code is available under the Common Development and Distribution License (CDDL), an OSI-approved free software license based on the Mozilla Public License (MPL).

There are some components with other licenses including BSD and MIT. We also include some software with the GNU General Public License (GPL) or the Lesser/Library General Public License (LGPL).

There still remain some binary-only, closed source components that we inherited from Oracle which we are working to replace. Unlike OpenSolaris, we do not require a closed source compiler.

Is illumos a community project?


Multiple community groups and interests (including people like you!) are stakeholders in the project, and anyone and everyone is welcome to contribute.

illumos was initiated by then-employees of Nexenta in collaboration with former OpenSolaris community members and volunteers. While companies including Nexenta, Joyent, and Delphix sponsor some of the work in illumos, the project is independent of their business decisions. illumos exists as a common base for multiple commercial and community distributions.

How do I start contributing?

illumos thrives on the efforts of its contributors. Have a look at the guide on How To Contribute if you want to submit code.

If you want to help in other ways then have a look at the Mailing Lists.

Most of the developers can be found on IRC and you're invited to drop in and say "hi!"

How do I build illumos?

See Building illumos.

How do I build a distribution based on illumos?

OpenSolaris was historically difficult to build as a distribution because it was assembled by many separate teams at Sun. The illumos community distributions are working to make this easier.

Some distributions have documented their build processes.

Is illumos compatible with Solaris/OpenSolaris?

illumos should run binaries and probably even kernel drivers from Solaris 10 update 10 and earlier, reflecting our strong commitment to backwards compatibility and interface stability.

More recent versions of Solaris, especially Solaris 11, are not considered compatible -- even if they sometimes seem to be! Oracle develops Solaris 11 as a proprietary fork of OpenSolaris, and has been diverging from illumos for nearly a decade at this point.

If you're building and testing software for Oracle Solaris, you need to do that on a Solaris system. Oracle now make available a Common Build Environment (CBE) image of Solaris 11 specifically for use in open source continuous integration environments.

What changes does illumos maintain?

  • Open internationalization libraries and data files.
  • Open replacements for closed binaries.
  • Community enhancements to critical technologies like DTrace and ZFS.
  • New open technologies.
  • Patches/bug-fixes we have independently developed, including security fixes.
  • Changes to ease community development.
  • ...and more!

And the name illumos?

We started off with the codename "FreeON", and later realized it is used by an existing project. We finally settled on illumos, after many hours of suggestions and counter-suggestions. illumos (pronounced i-llu-MOS and written in lowercase) ties in with Sun and light. It's the closest to ON we could get!