Odyssey was a codename for a version of Microsoft Windows that was in development from early 1999 to early 2000. The goal of Odyssey was to develop a successor to the NT-based Windows 2000 that was developed for business users. The same codebase, NT 6.0,was going to be used in creating Windows Neptune, the "home" counterpart to Odyssey. The version number "NT 6.0", but not the name, was later recycled for Microsoft's Windows Vista operating system. There were some publicly leaked builds of Neptune but Odyssey was never leaked. However, after the release of Windows 2000, the Neptune and Odyssey teams were combined with the Windows 2000 team to work on the Whistler project that was released in late 2001 as Windows XP.
Windows Neptune was a test version of Microsoft Windows that was in development from early 1999 to early 2000. The goal was to create a home user-friendly operating system from the same sources as the NT-based Windows 2000 that was developed for business users, replacing the older DOS-based Windows 9x home user operating systems. After the release of Windows 2000, the Neptune team was combined with the Windows 2000 team to work on Whistler, later released in the fourth quarter of 2001 as Windows XP,and Microsoft released another home user DOS-based operating system called Windows Me.
Nashville was the codename for a cancelled operating system upgrade for Microsoft Windows 95, which was originally intended to be released in 1996 as Windows 96. For Windows 95 users, Nashville was popularly referred to as Windows 97 (and eventually released as Windows 98). For Windows NT users, Nashville would be an interim revision between the releases of Windows NT 4.0 and Cairo, which was due at the same time as Memphis (after a series of delays, the next major version of Windows NT was finally delivered as Windows 2000). Due to its position between Windows 95 and Windows 97 (as Memphis was then known), the press often referred to Nashville as Windows 96. The most current build is 1276 but that build is rare. The most common build of Nashville is 999. The latest leaked Nashville build is 1276.
Cairo (operating system)
Cairo was the code name for a project at Microsoft from 1991 to 1996 (Cairo was also the codename of Windows NT 4.0). Its charter was to build technologies for a next generation operating system that would fulfill Bill Gates' vision of "information at your fingertips". Cairo never shipped, although portions of its technologies have since appeared in other products.