Open Source - Musharof Chy
rtmk
Realtime microkernel: preemptive, fully re-entrant, multithreaded, SMP, continuations, full locking...
Nilsen Elektronikk AS
Makes 2 very small, open source realtime OSs for embedded systems, written in C: proc Real-Time Ker...
CarbonKernel
RTOS simulator based on event-driven simulation methods with concurrent target debugging abilities,...
RTMX, Inc.
Makes RTMX O/S: IEEE POSIX realtime extensions to OpenBSD, with vendor specific ports for embedded,...
S.Ha.R.K.
Dynamic configurable kernel architecture to support hard/soft/non realtime use with interchangeable...
Linux Journal: Open Source Software for Real-Time Solutions
Compares 2 open source OSs for embedded uses: RTLinux, eCOS by Cygnus.
NicheTask
Open source multitasking embedded operating system with a proven track record, expressly designed f...
BeRTOS
A free real time operating system suitable for embedded platforms. Runs on several microprocessors ...
RadiOS
A microkernel based operating system, aims at binary compatibility with QNX Neutrino.
Contiki
An open-source operating system for the Internet of Things. It connects tiny low-cost, low-power mi...
Atomthreads
A free, lightweight, portable, real-time scheduler for embedded systems.