I was told so in email by Dave Weaver quite some time go when I debated that some long time back.

[link|http://www.os2bbs.com/os2news/OS2History.html|http://www.os2bbs.co...s/OS2History.html]


1990 - The Schism

In 1990, IBM and Microsoft were still working together on the development of OS/2. Microsoft, however, had found that Windows 3.0 - released in May 1990 - generated more revenue for them and therefore allotted increasingly more resource to Windows and correspondingly less to OS/2.

By late 1990, Microsoft had intensified its disagreements with IBM to the point where IBM decided that it would have to take some overt action to ensure that OS/2 development continued at a reasonable pace. IBM, therefore, took over complete development responsibility for OS/2 1.x, even though it was in its dying days, and OS/2 2.00. Microsoft would continue development on Windows and OS/2 3.00. Shortly after this split, Microsoft renamed OS/2 V3 to Windows NT.


[link|http://www.winnetmag.com/Article/ArticleID/4494/4494.html|http://www.winnetmag...ID/4494/4494.html]


Microsoft's internal project name for the new OS was OS/2 NT, because Microsoft's intention was for the new OS to succeed OS/2 yet retain the OS/2 API as its primary interface. The success of Windows 3.0 in April 1990 altered Microsoft's thinking and its relationship with IBM. Six weeks after Microsoft released Windows 3.0, Microsoft renamed OS/2 NT as Windows NT, and designated the Win32 API (a 32-bit evolution of Windows 3.0's 16-bit API) NT's official API. Gates decided that compatibility with the 16-bit Windows API and the ability to run Windows 3.x applications unmodified were NT's paramount goals, in addition to support for portions of the DOS, OS/2, and POSIX APIs. From 1990 to NT's public release in August 1993, Cutler's team was in a mad dash to complete NT, and the project grew to involve more than 200 engineers and testers. Figure 1 shows a timeline of the major events in the history of NT.