Free software implementation of the Solaris kernel.

illumos is a Unix operating system which provides next-generation features for downstream distributions, including advanced system debugging, next generation filesystem, networking, and virtualization options.

Community-driven illumos Distribution.
The OpenIndiana project is the open source community which develops, maintains, and supports the OpenIndiana distribution, an illumos based Unix-like operating system derived from OpenSolaris. The purpose of the OpenIndiana Project is to ensure the continued availability of an openly developed distribution based on OpenSolaris. The OpenIndiana project is also a continuation of the collaborative effort and community spirit of the OpenSolaris project.