The Mac OS X Public Beta (internally codenamed "Kodiak") was an early beta version of Apple Computer's Mac OS X operating system Cheetah. It was released to the public on September 13, 2000 for US$29.95. It allowed software developers and early adopters to test a preview of the upcoming operating system and develop software for the forthcoming operating system before its final release. It had a build number of 1H39. It's Apple menu was also in the middle of the menu bar, not at the left.

The Public Beta succeeded Mac OS X Server 1.0, the first public release of Apple's new NeXT OpenStep-based operating system, which used a variant of the classic Mac OS' "Platinum" user interface look and feel. The Public Beta introduced the Aqua user interface to the world. Fundamental user interface changes were revealed with respect to fonts, the Dock, the menu bar (with an Apple logo at the center which was later repositioned, due to public request). System icons were much larger and more detailed, and new interface eye candy was prevalent.

A software release life cycle refers to the phases of development and maturity for a piece of computer software—ranging from its initial development, to its eventual release, and updated versions of the released version to help improve software or fix bugs still present in the software.

Pre-alpha refers to all activities performed during the software project prior to testing. These activities can include requirements analysis, software design, software development, and unit testing.

In typical open source development, there are several types of pre-alpha versions. Milestone versions include specific sets of functions and are released as soon as the functionality is complete.

The alpha phase of the release life cycle is the first phase to begin software testing (alpha is the first letter of the Greek alphabet, used as the number 1). In this phase, developers generally test the software using white box techniques. Additional validation is then performed using black box or gray box techniques, by another testing team. Moving to black box testing inside the organization is known as alpha release.

OS X ( /oʊ ˌɛs ˈtɛn/), formerly Mac OS X, is a series of Unix-based graphical interface operating systems developed, marketed, and sold by Apple Inc. OS X (officially) runs exclusively on Macintosh computers and has been pre-loaded on all Macs since 2002.

OS X, whose X is the Roman numeral for 10 and is a prominent part of its brand identity, is built on technologies developed at NeXT between the second half of the 1980s and Apple's purchase of the company in late 1996. It was the successor to Mac OS 9, released in 1999, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 1984.

OS X is a UNIX-like operating system that originally ran on PowerPC-based Macs. In 2006, the first Intel Macs had a specialized version of Mac OS X v10.4 "Tiger". in 2007, Mac OS X 10.5 "Leopard", was the first to have UNIX 03 certification and run on both PowerPC and Intel Macs with the use of Universal Binaries. Mac OS X 10.6 "Snow Leopard" was the first version of OS X to drop support for PowerPC Macs and run solely on Intel's x86-based processors. Mac OS X 10.7 "Lion" was the first version of OS X to drop support for 32-bit processors and run exclusively on 64-bit CPUs.