ChorusOS started as the Chorus distributed real-time operating system at INRIA in the 1980s. Over the time, development effort shifted away from distribution aspects to real-time and modularization (componentization).
The latest source tree of ChorusOS, an evolution of version 5.0, has been open-sourced by Sun on experimentalstuff.com Chorus Open Source The Jaluna project has completed these sources and the current version the Jaluna-1 software is available at
Jaluna-1 is described there as a RT-POSIX layer based on FreeBSD 4.1, and the CDE cross-development environment. This software is still used according to the download server statistics