ChorusOS

ChorusOS is a microkernel real-time operating system built around a message passing model, grown from research begun in 1979 at INRIA, the French national computer science research institute, making it one of the earliest microkernels alongside Mach before it was commercialized by the startup Chorus Systemes SA. It later shifted from its original distributed computing focus toward real time embedded applications, ran on x86, Motorola 68000, PowerPC, SPARC, ARM and MIPS processors, and was POSIX compatible. Sun Microsystems bought Chorus Systemes in 1997 for its microkernel technology and used it inside JavaOS. Its last version, 5.1, was released as open source in 2011, and the system is now discontinued, though former developers continued related work through successor projects such as VirtualLogix. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/