Nukernel

NuKernel was a microkernel developed at Apple Computer during the early 1990s. Designed using concepts from Mach 3.0 with extensive additions for soft real-time scheduling to improve multimedia performance, it was intended to be used as the basis for the Copland operating system. Only one version was seen publicly, in the Copland "alpha" release, and proved to be extremely unstable. Development apparently ended with the ending of Copland development in 1996 and 1997.