As reported by [arstechnica]:

In a [previous post] we covered space rated computer hardware and the challenges of dealing with cosmic radiation. In this new article there's an indepth discussion on the Operating Systems often used on that hardware, which functions quite differently than your typical Windows or MacOS install. If your curious, they discuss platforms like the proprietary VxWorks, the open source RTEMS, SpaceChain OS, and chinas Sylix OS.