BeOS felt really fast, on a 200 mhz computer, several years ago. While the article's example is of Assembly optimized for performance over readability/maintaina

BeOS felt really fast, on a 200 mhz computer, several years ago. While the article's example is of Assembly optimized for performance over readability/maintainability (and I know people have written entire GUI OSs in Assembly, e.g. http://www.menuetos.net/ http://www.menuetos.net/), I know a clean, maintainable, responsive OS in a higher-level language is also possible. While I don't really know the details, I think BeOS had an asynchronous scheduling / interprocess communication model that was ahead of its time. (I'm not sure if parallels to Erlang apply.) And, I second that Acrobat is an unusually bad case, though a pretty commonly known example. (Few of you probably use the same HR software we do, for example... Not naming names.)