Windows 98 (codenamed Memphis while in development) is a graphical operating system by Microsoft. It is the second major release in the Windows 9x line of operating systems and the successor to Windows 95. It was released to manufacturing on May 15, 1998 and to retail on June 25, 1998.
Windows 98 is still referred to as "Memphis" by those who developed it.
Windows 98 was code named Memphis while in development, but it is unknown whether or not the developers still refer to it by it's code name. It may have been difficult because it involves unknown knowledge. 