Windows NT 3.1 and Windows NT 3.1 Advanced Server (named to associate it with Windows 3.1) were released on July 26, 1993, The architecture of Windows NT 3.1 was designed from scratch, and was originally intended to be a rewrite of the OS/2 operating system that Microsoft had co developed with IBM however, the popularity of Windows 3.0 resulted in a change to a more Windows like architecture, a change which subsequently resulted in IBM discontinuing its partnership with Microsoft.