Jason Johnson wrote:
> As far as what advantage this approach provides in general: it allows
> the VM to fully take advantage of multiple threads on a system without
> exposing "real" threading to the language.

But that's exactly what Hydra does (thus my question). Hydra uses 
separate object memories for (as you phrase it) "on OS-thread per 
scheduler". Therefore it allows all the existing code to continue to run 
with the current assumptions about threading (i.e., green threads only) 
and requires new code to be explicit about the concurrency model it 
assumes (i.e., channels for communication between the images).

Cheers,
   - Andreas