Microsoft executive Paul Maritz was targeting a release date in 1992, but the development schedule was uncertain. The company was eager to silence naysayers who speculated that NT wouldn't be on the market until 1994, and had planned to present the new OS at COMDEX in 1990. As Windows NT In May 1990, Microsoft released Windows 3.0, a new version of its MS-DOS-based Windows desktop environment. Windows 3.0 sold well, and the resulting shift in Microsoft's marketing strategy eroded their partnership with IBM—who wanted Microsoft to concentrate solely on developing OS/2 as its primary platform as opposed to building their future business around Windows. Users and developers were unsure of whether to adopt Windows or OS/2 due to these uncertainties (a situation magnified by the fact that the operating systems were incompatible with each other at the API level), while Microsoft's resources were also being drained by the simultaneous development of multiple operating systems. In August 1990, as a response to the popularity of Windows 3.0, the NT OS/2 team decided to re-work the operating system to use an extended 32-bit port of the Windows API known as Win32. Win32 maintained the familiar structure of the 16-bit APIs used by Windows, which would allow developers to easily adapt their software for the new platform while maintaining a level of compatibility with existing software for Windows. With the shift to a Windows-like architecture, the operating system's shell was also changed from OS/2's Presentation Manager to Windows' Program Manager. Due to these changes, NT was not presented at COMDEX 1990 as was originally planned. Neither the general public nor IBM knew about the transformation of NT OS/2 into Windows NT at the time. Although the companies did agree to a revised partnership where IBM and Microsoft would alternate developing major versions of OS/2 instead of collaborating on each version, IBM eventually learned of Microsoft's Windows NT plans in January 1991, and immediately ended the OS/2 partnership. IBM would solely develop OS/2 2.0 (as was planned under the amended version) and all future versions, without any further involvement from Microsoft. In October 1991, Windows NT received its first public demonstration at COMDEX. In an effort to ensure software taking advantage of Windows NT was available upon its release (scheduled for late-1992), Microsoft also distributed a 32-bit software development kit to selected developers in attendance. The demonstration was positively received; PC Magazine called Windows