[Haskell-cafe] Re: Python's big challenges, Haskell's big advantages?

[Richard A. O'Keefe]

It may be of interest that although Erlang has been doing
lightweight concurrency for >20 years,
  - you can choose whether you want to use an SMP version that
    has as many schedulers as there are cores (plus internal
    locking as needed) or a non-SMP version with one scheduler
    (and no internal locking); both versions are standard and
    it's only a performance issue, not a semantics issue
  - performance sometimes goes one way, sometimes the other
  - there was a "one UNIX process per Erlang process"
    implementation; I have a copy.  The community interest in
    it was, shall we say, massively underwhelming.

It might also be interesting to note that the experimental
operating system K42 from IBM does _all_ user-visible
threading in user-land.  This includes thread switching and
even I/O blocking and unblocking; all done in user-land.

I don't think we've begun to explore all the options yet.