The Computers: Software: Operating Systems: Microkernel: (ReactOS Microkernel )

ReactOS is a project to develop an open source operating system that is object code-compatible with Microsoft Windows NT applications and drivers. ReactOS Microkernel Operating Systems Software Computers.

ReactOS is an open-source operating system for x86 / x64 PCs intended to be binary-compatible with computer programs and device drivers made for Windows Server 2003. (wikipedia)