Is This True (Windows is 25)?

[MisterMe]

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The underpinnings of NT (and the API) are classic VMS. So much so, that it wasn't all that hard to port VMS code to NT. I did work on OS/2 briefly and really don't remember the API being anything like NT.

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You are correct. At very least, OS/2 was inspired by VMS. When it was released, OS/2 was a command line OS. The Presentation Manager GUI would come later. When Microsoft bailed on the partnership with IBM, it took MS-OS/2, replaced Presentation Manager with the Windows API, and named the "new" OS Windows NT (for New Technology). GUI-based OS/2 applications were incompatible with WinNT, but CLI-based OS/2 apps worked just fine in NT.

 

[Sun Baked]

Well the object oriented base for Mac OS X is 20 years old now, though the Apple GUI overlay and Apple bolt-ons aren't quite that old.