Advanced Projects
This is the list of advanced and more successful alternative operating systems, that somewhat grow more than being just a hobby or research operating system. Their success outside of the relatively tiny spheres of research and hobby operating system development means that they have an actual user basis, and a team is working on it (or has regular contributions). They are definitely more than a one-person-project. Forks, clones of proprietary OSes, as well as research projects sponsored by companies and/or universities belong in this list too.
Projects that are still in the hobby development phase but are mature, can be found at Notable Projects.
Everyone is welcome to add their own projects to the regular Projects list of all hobbyist operating systems.
