Releases and Active Development
  • The current release is 5.3 (download here). Note that this release branch was planned to be 4.12 but significant changes warranted bumping the major number (e.g. 4 to 5). The new release numbering scheme is described here.
  • The previous release series was 4.11 and the last release from that branch is 4.11.3 (download here).
  • The next release branch is planned to be 6. For details and status, visit the Release page. This is the git master.
  • Information on older releases is available here.

What is RTEMS?

The Real-Time Executive for Multiprocessor Systems or RTEMS is an open source Real Time Operating System (RTOS) that supports open standard application programming interfaces (API) such as POSIX. It is used in space flight, medical, networking and many more embedded devices. RTEMS currently supports 18 processor architectures and approximately 200 BSPs. These include ARM, PowerPC, Intel, SPARC, RISC-V, MIPS, and more. RTEMS includes multiple file systems, symmetric multiprocessing (SMP), embedded shell, and dynamic loading as well as a high-performance, full-featured IPV4/IPV6 TCP/IP stack from FreeBSD which also provides RTEMS with USB.

Major decisions about RTEMS are made by the core developers in concert with the user community, guided by the Mission Statement. 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 distributions, MS Windows, BSDs, Solaris, and Mac OS. We encourage everyone to contribute changes and feedback to RTEMS.

Commercial support is available from US and European companies, and free support comes via the active global community.

RTEMS News

April 29, 2010

OAR Corporation is proud to announce once again be teaching the Kick Start and Open Class. As RTEMS maintainer, I will once again be teaching these classes. This is the first time these have been offered in 2010. This is an unparalleled opportunity to learn about RTEMS from one of its...

April 23, 2010

RTEMS is pleased to announce that we received eight (8) student slots this year. In addition, we are pleased that three of the projects involve cooperation with other open source software projects (Go, Parrot, and...

April 22, 2010

SDO Initial Image NASA's recently launched Solar Dynamics Observatory, or SDO, is returning...

March 18, 2010

The RTEMS Project is very pleased to have been accepted as an organization in the 2010 edition of the Google Summer of Code. We encourage all potential students to join the mailing list and visit our IRC channel (#rtems on freenode.net). We will do...

March 18, 2010

The RTEMS Project is pleased to release 4.9.4. This is the fifth release from the 4.9 release series and is primarily a bug...

March 08, 2010

It is pretty obvious if you are reading this, but we now have a new website. Take a few minutes and look around. It is based upon Drupal and should provide a strong foundation for the future.

I would like to thank Chris Johns for his assistance in...

March 03, 2010

We here in RTEMS-land have been busy getting ready for the 2010 edition of the Google Summer of Code. We have already given a presentation to the IEEE-CS Student Chapter at the University of Tennessee at Chattanooga. Now...

February 19, 2010

(February 20, 2010) The wonderful people at the Google Open Source Program have added a blog entry on RTEMS and our success in the Google Summer of Code 2009. We are hopefully looking forward to...

February 11, 2010

This satellite includes five radiation hardened Coldfire CPUs running RTEMS. There are more details and links at the RTEMS Ramblings Blog. We are looking...

December 31, 2009

The RTEMS ticker test (a.k.a. sp01) was the first test created during the development of RTEMS. It sets the date and time to 9:00 pm on 31 December 1988. This coincides with the earliest part of the RTEMS Project. Since there is no birth certificate, we are treating this as RTEMS Birthdate....