Much has changed for Apple in the two-and-a-half years since it released the Tiger update to OS X. The company's iPod music player and iTunes Store continue to enjoy a stranglehold on their respective markets. Apple also moved its hardware over to Intel-built processors and introduced a new mobile phone, the iPhone, that's grabbed a tremendous amount of media attention.
So amid all that activity, where does its latest OS X update, Leopard, fit in? Don't be fooled by Apple's ever-widening business interests, analysts say - the Mac OS remains a critical part of Apple's overall strategy. And Mac OS X 10.5 in particular figures to play an essential role in the company's ongoing success.
"Mac OS X is key to Apple's message of the integration of hardware, software and services," said Ross Rubin, director of analysis at market-research firm NPD. "Given the focus of integration it's easy to lose track of the components of that strategy. Without the Mac OS, the computer is just a pretty Windows machine."
JupiterResearch vice president and research director Michael Gartenberg agrees: "It isn't quite as flashy in a year that brought us new iPods and the iPhone, but it's no less important."
While few would argue about the importance of this OS X update to Apple's fortunes, how to measure whether Leopard is a success or not is less clear.
Apple reported that it sold two million copies of Leopard in its opening weekend, but not everyone upgrades to the next version of an operating system all at once. There's also the question of factoring in the sales of Macs that come pre-installed with OS X 10.5.
NPD's Rubin says there are a few ways to judge the success of an operating system. First, you can look at the sales of boxed retail copies. You can also look at the percentage of the customer base that has upgraded after a certain period of time, a figure that would take into account sales of new hardware shipping with Leopard. Finally, you can look at the number of third-party developers that create apps to take advantage and further the platform.