See also:

• Computers: Software: Operating Systems: Open Source  (15)

• CarbonKernel - RTOS simulator based on event-driven simulation methods with concurrent target debugging abilities, mimics OS behavior, to implement and test embedded software on workstations. Descriptions, downloads, documents. [Savannah, Open Source, GPL]
• E.R.I.K.A. - Microkernel RTOSs and set of integrated tools to develop embedded realtime applications, made to support all architectures used in power train controllers in automotive industry. Kernels have 2 main layers: Kernel Layer, Hardware Abstraction Layer, HAL. [Open Source, GPL]
• NicheTask - A multitasking embedded operating system with a proven track record, expressly designed for embedded devices with limited resources.
• Nilsen Elektronikk AS - Makes 2 very small, open source realtime OSs for embedded systems, written in C: proc Real-Time Kernel, preemptive, mature; nesos Finite State Machine Operating System (FSMOS), modular, use concurrent programming methods in little time and space. Also: nemon Boot and Debug Monitor; Embedded Web Servers.
• RET & COM Research - Makes RadiOS, Radiant Operating System; realtime, multitasking, multiuser, for i386+, written in all assembly in NASM. Goal: create OS that combines all advantages of OS/2 and Unix; ftp downloads. [Public Domain]
• rtmk - Realtime microkernel: preemptive, fully re-entrant, multithreaded, SMP, continuations, full locking primitives; shares many ideas with Mach, developed by CMU in late 1980's, early 1990's, stopped in 1994. [GPL]
• RTMX, Inc. - Makes RTMX O/S: IEEE POSIX realtime extensions to OpenBSD, with vendor specific ports for embedded, dedicated systems, application specific Internet/intranet servers. Many fine features. North Carolina, USA.
• S.Ha.R.K. - Dynamic configurable kernel architecture to support hard/soft/non realtime use with interchangeable scheduling algorithms: fully modular in scheduling policies, aperiodic servers, concurrency control protocols; all not modular in most traditional OSs. Derived from HARTIK: HArd Real TIme Kernel. [GPL]
• Solar_OS - Also Sol_OS; goals: realtime, coded in 32-bit ASM, fast, very simple, small, cooperative multitasking, programs have full hardware control, modern OOP GUI, suitable for desktop targets. Open source, GPL.

• Linux Journal: Open Source Software for Real-Time Solutions - Compares 2 open source OSs for embedded uses: RTLinux, eCOS by Cygnus. (October, 1999)
• EE Times: Open source code smooths RTOS design - Benefits of open source compared to other RTOS licensing models. (July 26, 1999)