Norbert, you are confusing threads with fibers. OS Threads have never been, nor will ever be, "light-weight" in any sense of the word. If they were, no one would care about thread-pools and the like. Languages that feature light-weight threads, such as Erlang, are actually spawning fibers. The Erlang runtime, for example, only ever uses one D style thread to host millions of 'logical' threads.
Actually, newer versions of Erlang now use multiple threads, typically 1 per CPU and one pool of processes and a scheduler per thread. Processes can also be moved between threads in case one is busier than the others.
Casey
