"Andreas Raab" said:
>
> Absolutely. What we need is a *model* of concurrency (just like we have a 
> *model* for managing memory a *model* for sending messages, a *model* for 
> linked stack frames) and then have the VM implement that model of 
> concurrency as effectively as possible.

Out of curiosity, are those models exposed as Smalltalk objects?

My interest is not to have the most efficient VM implementation but to gain 
understanding on how the Garbage Collector or the PIC works.

I am thinking about something like Dan Ingalls presented in ESUG 2004 where 
he showed different Smalltalk versions (72, 76, 80) running on top of 
Squeak. He mentioned that the overall speed of the interpreted system was 
comparable to the original one running on the xerox machines.

Cheers,
Francisco