This project began with a simple C thread library, called the Micro Kernel, designed and written by Gord Cormack. The Micro Kernel evolved extensively into the μSystem, which provided sophisticated light-weight threads several years before the POSIX thread library for C. While much was learned about designing and constructing thread libraries during this project, the work has been abandoned because it was impossible to construct statically type-safe direct communication among threads (e.g., send/receive/reply cannot be made statically type safe, in general). The project has shifted to C++ (μC++), because the multiple entry points of a class allow direct communication to be statically type-safe.