There are many different operating systems, including Hurd (which is incomplete), TRON (there is a FOSS version called "B-Free" but seems to be incomplete and a

There are many different operating systems, including Hurd (which is incomplete), TRON (there is a FOSS version called "B-Free" but seems to be incomplete and abandoned), and others. I also have many of my own ideas about operating system design, some of which are inspired by other designs but with some differences.