The Real-Time Executive for Multiprocessor Systems or RTEMS is a open source fully featured Real Time Operating System or RTOS that supports a variety of open standard application programming interfaces (API) and interface standards such as POSIX and BSD sockets.
It is used in space flight, medical, networking and many more embedded devices across a wide range of processor architectures including ARM, PowerPC, Intel, Blackfin, MIPS, Microblaze and more. You can obtain commercial support or support via the active community.
Major decisions about RTEMS are made by the core developers in concert with the user community, guided by the Mission Statement. We encourage everyone to contribute changes and help testing RTEMS. We provide access to our development sources via a Git Repository (see these Instructions for details). We strive to provide regular, high quality releases, which we want to work well on a wide range of embedded targets using cross development from a variety of hosts including GNU/Linux, Mingw, MS-Windows, FreeBSD, Cygwin, and Solaris.