You may have seen some reports doing the rounds today that a "secret project" was initiated at Apple to port the underlying guts of OS X (AKA Darwin) to ARM chips, and that those duties were handled by a then-intern named Tristan Schaap. The story goes that Schaap was part of a team tasked with manufacturing a build of Darwin for the Marvell MV88F6281 processor, and that upon completion of the project, he was hired on by Apple as a CoreOS engineer. While the latter part is accurate — Schaap does appear to be part of that team — the rest of it doesn't make sense on a number of levels, the most notable being that the essence of OS X (certainly much of its codebase) has already been adopted for products which you may have heard of or even used once or twice. Namely, every iPhone, iPod touch, and iPad ever made.
As OSNews astutely points out, Schaap was merely moving lower level pieces of Darwin code to the Marvell chip, not bringing over the full OS X you know and love. Furthermore, a cursory search for that particular CPU reveals that it's primarily in use in some of Apple's networking products, like the Time Capsule and Airport Extreme. And guess what? In the thesis (page 26 of the PDF, to be exact), Schaap reports that device testing was done on the K30A — Apple's internal name for the second generation Time Capsule. After a little bit of digging, we stumbled upon an interesting fact: those products aren't currently running Apple's Darwin core, but rather utilizing NetBSD, an open source, Unix-esque OS widely used in networking devices. We're told that it's possible Apple is in the process of getting its core OS onto all of its products (we know the company isn't a fan of third-party code), so the project that Schaap based his thesis on is very likely one and the same.