ChorusOS is a microkernelreal-time operating system designed for embedded systems. Sun Microsystems acquired Chorus Systèmes, the company which created ChorusOS, in 1997. Sun no longer supports ChorusOS. The founders of Chorus Systems started a new company called Jaluna in August 2002. Jaluna has subsequently become VirtualLogix. VirtualLogix designs embedded systems using Linux and ChorusOS (which they call "VirtualLogix C5"). C5 is described by them as a carrier-grade operating system, and is still actively maintained by them.
ChorusOS started as the Chorus distributed real-time operating system at INRIA in the 1980s. Over 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
http://sourceforge.net/projects/jaluna/. 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.
