Atheos is a project by Kurt Skauen to develop a pervasive multi-threaded operating system with a gui built into the kernel. As of 2001/10 this can best be defined as an experimental system which is aiming at full posix compliance.
It is now starting to attract programmers from beos.
As of 2005/04 we have spotted that while the site is still up, it is only showing the front page. This is because the project has moved to being hosted on sourceforge. Unfortunately he forgot to link the two together properly, and the sourceforge link says the project has gone. (2009/05/09)
In the meantime, there was a fork in the code, producing Syllable