The Scoop on the Xbox 360's Embedded OS?

An anonymous reader writes "When the Xbox 360 was launched two weeks ago amid much brouhaha over its custom-designed IBM PowerPC-based CPU with 3 symmetrical cores running at 3.2GHz each, WindowsForDevices.com wondered aloud, 'What OS runs inside the Xbox 360?' Now, the website thinks it has found the answer to its question. No, it's not Linux or BSD, nor a derivative of Longhorn or Windows CE."