Windows NT

In 1988, Microsoft hired Dave Cutler (the creator of DEC's VAX/VMS OS) to create an OS for Microsoft: Windows NT.

Windows NT became the foundation for Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10.

A specific architectural goal of Windows NT were the subsystems.

Because at the time of designing Windows NT, Object Oriented languages were on the rise, in Windows NT, everything is an object (as opposed to Linux, where everythying is a file).