Maybe he's just tired of the Apple iPod getting all the press. Or maybe it's that his beloved Mac OS X has never really met with mainstream success. Whatever the reason, Apple CTO Avie Tevanian, widely heralded for his creation of the Mach microkernel that sits at the heart of OS X (and NeXTStep before that), has decided to leave the company to pursue other interests. Tevanian will leave Apple on March 31, leaving behind him a company that seems a lot more interested in digital music than computer OSs