RTEMS

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RTEMS
Developer	OAR Corporation
Written in	C
OS family	Real-time operating system
Working state	Current
Source model	Open source
Initial release	1993; 32 years ago (1993)
Latest release	6.1 / January 22, 2025; 5 months ago (2025-01-22)[1]
Repository	gitlab.rtems.org/groups/rtems/
Marketing target	Embedded systems
Available in	English
Platforms	ARM, Blackfin, ColdFire, TI C3x/C4x, H8/300, x86, 68k, LatticeMico32, Microblaze, MIPS Nios II, OpenRISC, PowerPC, SuperH, SPARC (ERC32, LEON), SPARC64
Kernel type	Real-time
Default user interface	Command-line
License	BSD 2 Paragraph
Official website	www.rtems.org

Real-Time Executive for Multiprocessor Systems (RTEMS), formerly Real-Time Executive for Missile Systems, and then Real-Time Executive for Military Systems, is a real-time operating system (RTOS) designed for embedded systems. It is free and open-source software.

Development began in the late 1980s with early versions available via File Transfer Protocol (ftp) as early as 1993. OAR Corporation managed the RTEMS project in cooperation with a steering committee until the early 2000's when project management evolved into a subset of the core developers managing the project. In 2014, hosting was moved from OAR Corporation to the Oregon State University Open Source Lab hosting.