@ Plaupius
The core of the OS was heavily low-level optimised, higher level parts were mostly written in a C-like laguage (same roots) and later were rewritten in C.
The classic 32-bit AmigaOS development frameworks were technically very advanced for its time (80s) with shared libraries, universal scripting support, datatypes (for example allowed ancient paint/word processor/spreadsheet programs to use new image formats they were not designed for like PNG, etc) etc. There were many different dev tools and framework/GUI addons/replacements and after C= went out of business there was a lack of direction which eventually split up the development community into various different directions.
The OS is being revived by devs who loved the system:
http://en.wikipedia.org/wiki/AmigaOS_4







