Windows Whistler
In the late 1990s, initial development of what would become Windows XP was focused on two individual products; "Odyssey", which was reportedly intended to succeed the future Windows 2000, and "Neptune", which was reportedly a consumer-oriented operating system using the Windows NT architecture, succeeding the MS-DOS-based Windows 98. Based on the NT 5.0 kernel in Windows 2000, Neptune primarily focused on offering a simplified interface. A single build of Neptune, 5111, revealed early work on the activity center concept, with an updated user account interface and graphical login screen, common functions (such as recently used programs) being accessible from a customizable "Starting Places" page (which could be used as either a separate window, or a full-screen desktop replacement). It was later confirmed that Microsoft were planning a successor to Neptune known as Triton, although it was originally thought to be a service pack to Neptune.