Project Oberon - The Design of an Operating System, a Compiler, and a Computer
Also, a language.Oberon-2 language has Pascal-like syntax, with Java-like features (classes, single inheritance, interfaces, garbage collector, sane module system instead of includes). Unlike Java, no VM is required, at least in the system that I used. Like Java and unlike C, it is impossible to write unsafe code accidentally - you have to go out of your way to access unallocated memory regions or break type safety.Decent module system and straightforward grammar has also allowed writing simple and very fast compilers. It was fun to work with.