Apple’s Mac Chief Departs as Big Changes Come to OS X

Apple (s aapl) SVP of Mac Software Engineering Betrand Serlet is leaving the company, according to a press release issued by Apple. He will be replaced by Craig Federighi, Apple’s VP of Mac software engineering. Frederighi’s chief responsibility at Apple has been OS X development.

Serlet, who joined Apple in 1997 and worked with Steve Jobs at NeXT before that, and  his key roles at the Mac-maker include helping in the initial design creation, and evolution of the Mac OS X operating system. Serlet, who has a doctorate in Computer Science from the University of Orsay in France, is said to be leaving the business in order to pursue more scientific pursuits. In his own words:

I’ve worked with Steve for 22 years and have had an incredible time developing products at both NeXT and Apple, but at this point, I want to focus less on products and more on science. Craig has done a great job managing the Mac OS team for the past two years, Lion is a great release and the transition should be seamless.

Federighi, who replaces Serlet, also spent time at NeXT with Steve Jobs, and joined Apple, too, before leaving for Ariba (s arba), a collaborative business commerce company. He spent 10 years at Ariba, eventually becoming CTO, and returned to Apple in 2009 to head OS X engineering efforts. He holds a Master of Science degree in Computer Science from the University of California.

The departure of Serlet comes as Apple continues to move toward the type of computing represented by its iOS mobile platform. OS X Lion, which is available as a developer preview, borrows many features and much of its user interface changes from the mobile platform. In that light, it’s easy to think of Serlet’s departure as a sign that Apple is putting the desktop roots of OS X behind it. OS X is essentially Serlet’s creation in many ways, and has been the single focus of his job since Apple created the iPhone and two, distinct OS platforms. Federighi is a relative newcomer to OS X, and benefits from not having been closely involved in that operating system’s creation, leaving him with broader vision as to what it might become.

Another possibility pundits are bound to suggest is that Serlet realized he would never see top billing at the company as CEO, with so many other well-qualified candidates occupying Apple’s higher ranks. A departure now could give him the opportunity to step into that role at another organization. This isn’t too likely, though, given that Serlet has worked with Jobs for 22 years and probably had a very good idea of how high he could climb at Apple.

Whatever the reason, Serlet’s departure definitely marks the end of an era at Apple. He may not have been the company’s most public executive, but he was instrumental in creating the Mac experience that defined Apple’s approach to computing for more than a decade.