A key excerpt from the article: ‘This combination is referred to as GNU/kWindows (GNU with the Windows kernel added). Microsoft and Canonical have apparently

A key excerpt from the article: ‘This combination is referred to as GNU/kWindows (GNU with the Windows kernel added). Microsoft and Canonical have apparently been working together to write a subsystem that translates Linux system calls into something Windows will understand—a compatibility layer. So, software compiled to run on a system with the kernel Linux will work on Windows through system call translation. Many articles are calling this system “Ubuntu on Windows”, or “Linux on Windows”. This is a fallacy: the kernel Linux is not at all involved! What we are witnessing is the GNU operating system running with a Windows kernel instead of Linux.’