About RTEMS

What is RTEMS

Real-Time Executive for Multiprocessor Systems (RTEMS) is an open source fully featured Real Time Operating System (RTOS) that supports a variety of open standard application programming interfaces (API) and interface standards such as POSIX and BSD sockets. It is widely used in space flight, medical devices, networking and many more embedded systems across a wide range of processor architectures including ARM, PowerPC, Intel, SPARC, MIPS, RISC-V, Blackfin, MIPS, Microblaze and more.

Over the past twenty years, RTEMS has been selected as the RTOS in flight controllers and science payloads for satellites and probes by space agencies around the world including the European Space Agency (ESA) and National Aeronautics and Space Administration (NASA). As part of these missions, RTEMS has been in orbit or is currently orbiting five (5) planets and the sun and is on the surface of Mars as part of the Curiosity Rover. High profile NASA missions using RTEMS include the Mars Reconnaissance Orbiter, Dawn, Fermi, Magnetospheric Multiscale, Solar Dynamics Observatory, Parker Solar Probe, and Juno. RTEMS is currently one of the RTOS products that sits underneath key NASA space software frameworks such as their core Flight System and core Flight Executive products. ESA has used RTEMS on many cornerstone missions including Herschel, Planck, the BepiColumbo mission to Mercury, and ExoMars. In addition, the entire European Galileo GPS satellite constellation uses RTEMS as the RTOS. RTEMS Releases 4.5, 4.6, and 4.8 have been flight qualified by ESA and the current version of RTEMS, containing support for Symmetric Multiprocessing (SMP), is currently being pre-qualified by ESA for flight.

RTEMS License

RTEMS is free software; you can redistribute it and/or modify it under terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. RTEMS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with RTEMS; see file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

As a special exception, including RTEMS header files in a file, instantiating RTEMS generics or templates, or linking other files with RTEMS objects to produce an executable application, does not by itself cause the resulting executable application to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU Public License.

Other modules of licenses govern their respective packages including but not limited to TCP/IP Stack License, RPC/XDR License, GoAhead Webserver License (requires graphic to be displayed on website hosted), and the Stanford University Permissive License

Open Source Community

For more information about RTEMS and its Open Community please see the RTEMS Community site