title: Is Concurrent Haskell still restricted to a single OS thread?
body: <p>In a 2005 research paper it said </p>
  
  <blockquote>
    <p>Concurrent Haskell is currently implemented only for a uni-processor. The runtime schedules lightweight Haskell thread within a single operating system thread. Haskell threads are only suspended at well-deﬁned “safe points”; they cannot be pre-empted at arbitrary moments. </p>
  </blockquote>
  
  <p>Has this changed or is Concurrent Haskell still restricted to a single OS thread?</p>