Happy 10th birthday, Mac OS X!

It's hard to believe that 10 years ago today, Mac OS X made its official debut after several months of a paid public beta. Mac OS X v.10.0 "Cheetah" was released on March 24, 2001 for US$129. It was slow, clunky and made many users want to throw their Macs out the window, into the closest body of water or quickly scurry back to the safety of OS 9. Despite the plethora of errors, it was clear that 'Classic' Mac OS's days were numbered.

The anniversary comes a day after one of Mac OS X's major development leaders, Bertrand Serlet, announced that he was leaving Apple. Serlet helped guide the transformation of the NeXTStep OS purchased by Apple into the Mac OS X (and eventually iOS) that we know and love.

In the rest of this post, we share the seven (soon to be eight) major releases of Mac OS X (10.4.4 is considered a major release because of the rewrite for the Intel platform) and video blasts from the past as we share footage of the original announcements and previews of Mac OS X. Check out the gallery of UI changes as well.

10.0 Cheetah -- March 24, 2001

Although riddled with bugs, Cheetah introduced the Mac world to now-familiar features such as the Dock, Terminal, Mail, Address Book, TextEdit, AppleScript and PDF support along with full multitasking, Aqua and OpenGL. However, this first version of the Aqua user interface was slow, and kernel panics were frequent. Many key productivity and creative applications weren't ready for the new platform, meaning that the Classic compatibility environment was running almost all the time.

10.1 Puma -- September 25, 2001

Puma was released as a free update to those who bought 10.0 in an effort to fix all that was wrong with Cheetah. Although some argued that Puma still wasn't fully developed, this cat proved to be more stable than its predecessor. This is the version of the OS that brought us easier CD and DVD burning through the Finder and iTunes, DVD playback, better printer support, ColorSync 4.0 and Image Capture.

Video find thanks to the awesome Blake!

10.2 Jaguar -- August 24, 2002

Jaguar (or, if you prefer Steve's pronunciation, "Jagwire") was the first version of Mac OS X that many considered ready for prime time. In addition to stability and speed fixes, Jaguar featured a revamped Finder and Address Book, Quartz Extreme, Bonjour, network support for Windows, Inkwell tablet support and more.

10.3 Panther -- October 24, 2003

Panther was the first version of Mac OS X that wasn't able to run on certain older PowerPC Macs, such as the earliest Power Mac G3s and PowerBook G3s. Again, the software featured a number of revisions to existing features and also introduced Expose, Font Book, iChat, FileVault and the Safari browser (now cross-platform).

10.4 Tiger -- April 29, 2005

In a sense, there are two major releases of Tiger. The first was the operating system's original release in April 2005. Then, there was 10.4.4 -- codenamed Marklar, and first demoed to the public at WWDC in June of 2005 -- which brought Mac OS X to Intel-based Macs in January 2006. The platform port of the OS was a major engineering effort conducted largely in secret (using code from the original Rhapsody OS along with, among other things, libraries that began their life as part of the QuickTime for Windows project) and the announcement came as a shock to the Mac community. Along with the Intel-compatible version of Mac OS X, Apple announced Xcode 2.1 to allow cross-architecture development; third-party IDEs like CodeWarrior would not compile apps for the new Mac hardware.

Although, at the time, Jobs considered the Intel release a major revision of the system, it was not counted as one of the major OS X releases during the Lion preview earlier this year.

As Safari, iChat and Mail were further refined, new features were introduced, such as Dashboard, Automator, Dictionary, Front Row and Quartz Composer. Boot Camp (allowing Mac users to run Windows natively on Intel machines) first appeared here as an optional install.

10.5 Leopard -- October 26, 2007

More than two and a half years after Tiger's release, Apple finally released Leopard after pushing back the release date several times. This became the first post-iPhone version of OS X and brought us Back to My Mac, Boot Camp as a standard install, Spaces and Time Machine. It is also the first version of Mac OS X not to include the Classic emulation layer, taking away access to OS 9 applications for PowerPC users, and was the first version of Mac OS X to offer full 64-bit compatibility for applications. Leopard is also 'true UNIX,' meeting the Open Brand specification for UNIX (the first BSD-based operating system to meet that standard).

10.6 Snow Leopard -- August 28, 2009

After another nearly two-year wait, Snow Leopard was released as a stability and performance successor to Leopard. As such, it is the only version -- other than the upgrade from Cheetah to Puma -- not to carry the $129 price tag. Those who owned Leopard only paid $29 for the new system. It is also the first version of Mac OS X not to support PowerPC Macs, and the Rosetta compatibility library for PPC applications is now an optional install. AppleTalk is also no longer supported. Revisions to the Finder, Preview and Safari were included; QuickTime X, Grand Central and OpenCL were introduced.

10.7 Lion -- anticipated Summer 2011

As recently revealed, Lion will combine the best of the iOS platform with the Mac. We've already gotten some glimpses of the future with the release of the Mac App Store, and there is more to come. Announced features for Lion include Launchpad, a display of your Mac apps that is similar to iOS; full-screen apps; Mission Control, which allows you to see what's running on one screen; Versions; Resume; AirDrop and more.

Share your memories of Mac OS X with us in the comments and let us know your expectations for Lion and future releases of the OS! Here's to another decade of innovation and cool computing.