It's been three years and a day since Mac OS X hit stores worldwide. Mac users have now seen four iterations of the operating system, and at £99 a time some have paid out nearly £400 for the privileged of running what Apple described as "The world’s most advanced operating system", when it launched on March 24, 2001.

Ars Technica has posted a potted history of Apple's Unix-based OS. Taking readers though the three years of OS X releases that have seen it move from OS X 10.0 Cheetah – described as a beta – to the current OS X 10.3 Panther.

Cheetah to Jaguar The Arstechnica report said: "OS X was more stable than OS 9.1, I liked using it. I quickly realized that this release was not really ready for prime time."

It describes "rough edges", including the fact that DVDs didn't work: "You could read data off them, but you couldn't watch them. Printer drivers were few and far between, and CD burning? Forget about it. Legacy support? Forget about that too."

The highlight of OS X 10.1 (Puma) was that it "no longer felt like a beta".

"The trickle of OS X-native applications began to turn into a stream." These applications included Microsoft's carbonized version of Office, Macromedia Freehand, Adobe Illustrator and Photoshop.

"Other OS X software got faster, notably QuickTime, and overall stability improved markedly."

"For many people Jaguar delivered the goods. Many felt it was all that the original 10.0 release should have been, and were upset at having to pay $129 (£99) for functionality that should have been present in Cheetah or at the very least, Puma."

Jaguar was the first version of OS X to be advertised by its code name. According to the report the highlight of Mac OS X 10.2 was Quartz Extreme. "The new tech offloaded the window compositing calculations to the GPU instead of handling everything in the CPU. This meant that for the first time with OS X, the CPU was freed up from thinking about how to draw windows. The difference was quite noticeable."

Other improvements with Jaguar included a spam blocker, address book, iCal, iSync, iChat and Rendezvous.

Panther time

According to Arstechnica: "The most useful new feature in Panther, and the one with the most "gee whiz" bang for the buck, has to be Exposé."

Panther also bought with it the brushed metal interface that had been introduced with iTunes and QuickTime and used in Safari.

"The sidebar was another big Apple UI change with Panther. One morning, Steve Jobs woke up, looked at his PowerBook, and realized that the screen was wider than it was tall and decreed that the icons should move to the side of the Finder windows from the top," according to Arstechnica.

Panther also had some significant under-the-hood Unix tweaks, Apple's own X11 implementation shipped with Panther, as did Xcode, their developer tools.

The report concludes: "There are times when Panther still feels like a work in progress, and it would be great if some of the functionality and UI changes rolled out in Panther had been there from the start.

"After three years, Mac users have a modern, mature, and stable desktop OS. While there have been some hiccups along the way, Apple has generally done a good job rolling out new features in the four major releases."