There are a lot "See also" - so I'd like to shout out to the late Terry Davis' "TempleOS" and his ... strange take on an interactive boot-to-command line system based on C++ and x86_64.

[*] https://en.wikipedia.org/wiki/TempleOS

[Edit]: See also http://www.codersnotes.com/notes/a-constructive-look-at-temp...