Ultimately, the business and consumer lines of Windows were merged in Windows XP, released in 2001, and the NT kernel became the core of XP and all subsequent versions of Windows -- which means that except for a scattered few diehards still using the Windows 3.x and 9x lines, all of today's Windows users are using a direct descendant of NT.

A lesser-known product success story is Microsoft SQL Server, which has a somewhat checkered history. It began in 1988 as a joint venture among Microsoft, Sybase and the now defunct Ashton-Tate, and was designed for the troubled .

The product was largely a port of Sybase SQL Server 3.0, which ran on a variety of operating systems, including Unix and VMS. Microsoft and Sybase ultimately parted ways, with Microsoft developing SQL Server for Windows NT and Sybase changing the name of its version to Adaptive Server .

These days, SQL Server has grown to become the third most popular database software in the world, behind those of and IBM.