You missed TempleOS [wikipedia.org]. It's a bit of a legend.
TempleOS is a 64-bit, non-preemptive multitasking,[5] multi-core, public domain, open source, ring-0-only, single address space, non-networked, PC operating system for recreational programming.[6]
TempleOS was written in a programming language ... called "HolyC".
HolyC is the just-in-time compiled language of TempleOS. It is an imperative, statically typed programming language, although it uses some object-oriented programming paradigms.
(Score: 2, Touché) by pTamok on Wednesday February 25, @01:27PM
You missed TempleOS [wikipedia.org]. It's a bit of a legend.