Mac OS X, the operating system used today by every single Mac available from Apple, has quite an extensive history, as does the Mac OS in general. Mac OS X has seen many different variations, as it started off with version 10.0 “Cheetah” and is currently on version 10.8 Mountain Lion. Every single Mac OS X version to date has been named after a big cat, from Puma to Panther to Leopard to Lion.
March 24th of this year marked 11 years that the desktop version of Mac OS X has been in existence (Mac OS X Server 1.0 launched two years earlier in 1999), and throughout those 11 years it has heavily evolved, even dropping the “Mac” before OS X officially as of the Mountain Lion developer preview release.
The transformation from the former versions of Mac OS to Mac OS X was quite significant in that it moved away from the more simplistic nature of the former Mac OS versions, introducing more complex applications and application suites such as iLife and Front Row and other significant new features such as pre-emptive multitasking.
Mac OS X also made the switch from using the Arabic numbering system to using the Roman numeral X, which remains to this day and will likely carry on into the next major Mac OS release (presumably OS XI).
The most significant and well-known change that came with Mac OS X, though, was the introduction of the Aqua theme, which succeeded Mac OS 8 and 9’s Platinum theme. To this day, Mac OS X is easily identified thanks to the Aqua GUI theme, although its inclusion in more recent versions has died down thanks to the “iOS-ification” of Mac OS X that has begun taking place.
Mac OS X continued to evolve through its eight variants (nine counting the upcoming Mountain Lion), through the introduction of new features such as the Safari web browser in 10.3 Panther, Spotlight in Tiger, and so many others. The Mac OS undoubtedly evolved the most from Mac OS X 10.0 to the current 10.8, which also brought some significant new features such as Launchpad and Resume.
There is no telling what Apple has planned for Mac OSX (or OSX, as it’s now called) in the future, although it is highly speculated that the desktop OS will eventually merge with Apple’s mobile iOS, and it certainly seems like it’s on that path with the new features that have been added in Lion and now Mountain Lion 10.8. Only time will tell where Apple actually plans to lead Mac OS X in the future without the leadership of now former CEO Steve Jobs.