ReAl

scmRTOS is a small simple real-time OS for microcontrollersdesigned by Harry Zhurov.

Project page on sourceforge.net.
scmRTOS google group.
scmRTOS Wiki
scmRTOS section, on electronix forum (Russian).

Here i offer you the detailed explanation of 1-EventFlag – one of the examples, distributed with the system.

Sorry, English translation not ready yet, you can review an Ukrainian version.