Apple&39's Craig Federighi, who is taking over for the departing Bertrand Serlet.

Craig Ferderighi is an Apple "boomerang."

Federighi, who's taking over for departing Mac veteran Bertrand Serlet, left Apple in February of 1999 for business software company Ariba, and wound up coming back 10 years later to help Apple build the Mac OS, which ships on the company's desktop and notebook computers.

Now, according to Apple's announcement earlier this week, he's stepping into a role many are watching closely: he'll be running the Mac OS group at a time of uncertainty as to what, exactly, a computer is--what form factor it's in' what software it's using.

The Mac OS has played a crucial role in Apple's hardware strategy over the past decade. Unlike the case with Microsoft's Windows, you can only buy the Mac OS for Apple-made hardware, and the company has built a business out of trying to produce new iterations of it at a faster pace than competitors. The next step in the operating system's evolution, as unveiled by Apple back in October, is to bring some of the features and familiarities of the company's mobile iOS platform back to the Mac OS. How that integration happens, and where it's going, largely rests on who's in charge of the OS.

CNET reached out to Apple to speak with Federighi about his new role, but that offer was never taken up.

Federighi can most easily be described as a "geek god." He's a man who after buying an $8 million house in Los Altos, Calif., could still be found staying up late on community message boards, helping people get his company's product to work. Nearly two decades ago he was also a self-described fan of martial arts star Jackie Chan and of bad haircuts.

Federighi's first stint at Apple began in 1996 after Apple acquired Next, the company founded by Steve Jobs after Jobs had left Apple a decade earlier. At Next, Federighi had been the Enterprise Objects Framework project manager.

EOF was launched by Next in 1994 as an object-relational mapping tool, giving developers a way to hook up multiple databases to one another and to the Web without having to write the code to make that happen. The technology would later become part of WebObjects, Next's object-oriented Web application server, which Apple now packs in as part of its Xcode developer tool set.

In 1999, Federighi left his role as the director of engineering at Apple to join Ariba, a business software company that had just gone public. Federighi began there as the vice president of Internet services before later being promoted to executive vice president and chief technology officer. His final role before departing back to Apple was as Ariba's "user interface technology evangelist," with the company having given the CTO spot to Bhaskar Himatsingka.

Ariba continues to be one of the survivors of the dot-com bust. Following its IPO in 1999, which was right around the time Federighi signed on, its stock made a dramatic jump, only to come down again following the crash. The company continues to make commerce software and tools including its Commerce Cloud platform, which it says is used by more than 340,000 companies.

Inventor, forum-goer Federighi is credited as a co-inventor on three U.S. patents, all of which are owned by Apple. The earliest of the bunch, titled "object graph editing context and methods of use" was applied for in 1996 and issued three years later to Next. Federighi is listed as the lead inventor on the technology, which encompasses parts of WebObjects. Following the first, a patent that was filed for in 1999 deals with "distributing and synchronizing objects." The third, which dealt with graphical user interfaces was applied for in 2001 and was a continuation of one of Apple's patent applications from 1997.

Federighi's technology background can be traced back to college. He got his masters in computer science from the University of California at Berkeley, just an hour or so north of Apple's campus. There he also earned a bachelor of science degree in electrical engineering and computer science.

While at UC Berkeley, Federighi penned a technical report published by the Electrical Engineering and Computer Sciences group at the school's College of Engineering and co-authored with Lawrence A. Rowe, who currently sits as the president of the Fuji Xerox-owned subsidiary FX Palo Alto Laboratory. The report detailed "a design of a distributed video-on-demand system that is suitable for large video libraries." Such a system was designed to serve video locally for those on Berkeley's campus, as well as over the Internet at large. The idea was that it could be used as a means for people to pull up things like lecture videos, along with personal videos and audio.

In doing research for a report on video editing systems two years earlier, in 1992, Federighi turned to a Usenet video recording forum to ask for help, asking for advice on where he could find references and articles. He also used the system to help find a fourth roommate for the shared house he was living in at the time, where he disclosed the group's aforementioned affinity for Jackie Chan movies and bad haircuts. In another posting from 1993, Federighi jumped in on a thread about connecting floppy drives to Next computers, sharing his experience of having a disk drive literally go up in smoke after he accidentally reversed the connector cable:

Federighi has since gotten his revenge on floppy drives, returning to work for the company that is credited, in part, with helping kill them off.

The new spotlight Since rejoining Apple, Federighi has made two appearances in Apple keynote presentations. The first was during the unveiling of Mac OS X 10.6 at Apple's Worldwide Developers Conference in 2009, the same year he came back:

More recently, he could be seen briefly during Apple's Back to Mac event, where the company first took the wraps off the upcoming point release of Mac OS X 10.7, dubbed "Lion." There, Federighi went through a quick, seven-minute demo of some of the headlining features that will make their way into 10.7:

Federighi is likely to get more of the public spotlight now that he's taking over for Serlet, who had been a regular during Mac keynote presentations at the company's annual Worldwide Developer's Conference. That's when Apple has historically taken the wraps off new versions of the Mac OS. And it's when the Mac product team shows off what's new and how it works to developers who plan to build applications on the operating system. The developer's conference cycle was knocked slightly off kilter with 10.7, when Apple first unveiled the upcoming operating system at an event to press.

The public spotlight will also be placed on the Mac OS team itself, since one of the big questions that remains is where the desktop operating system is headed. Will its quick release cycle remain, or will Federighi push to change the pace And how much more of iOS, which was first billed as an offshoot of OS X, will the Mac OS absorb Federighi now finds himself a larger figurehead in that debate.