Minoca OS is a leading-edge, highly customizable, general purpose operating system. It features application level functionality such as virtual memory, networking, and POSIX compatibility, but at a significantly reduced image and memory footprint. Unique development, debugging, and real-time profiling tools make getting to the bottom of issues straightforward and easy. Direct support from the development team behind Minoca OS simplifies the process of creating OS images tailored to your application, saving on engineering resources and development time. Minoca OS is a one-stop shop for systems-level design.
Since this will be the main question: no, it is not open source (count the buzzwords). There's a free version that's free to use in non-commercial settings, and a pro version that isn't free, but does come with source access. So no, not open source - but not everything has to be. It's not like open source operating system folks are starved for entertainment in that department.