FreeRTOS is a portable open source (GPL) real-time operating system for embedded devices. It offers a smaller and easier real-time processing alternative for applications where eCOS and embedded Linux (or Real Time Linux) won't fit, are not appropriate, or are not available. FreeRTOS runs on a
bunch of architectures, both 8- and 16-bit. TCP/IP support is provided either from the
uIP software TCP/IP stack (live demo server
here) or by using the
Wiznet hardware TCP/IP co-processor (live demo server
here).