The following idea traversed my mind reading the previous thread about 
ancient. May be I am missing something,
So I hope the expert could tell me if they think this is possible/good 
idea/bad idea

We could add to OCaml a third generation with the following properties:

- Objects are moved to this third generation either manually (or created 
there) or automatically after
  surviving k major GC (k may be ajustable at runtime ? k = 0 means never ?)

- Objects in the third generation can be shared between processes (like 
in Ancient)

- There is a global greyval table, protected by a mutex, and an object 
must be added in the table of greyval
when mutated if it is a pointer pointing to the major or minor heap of a 
specific process. Then, the object stops
to be accessible for reading by other processes (Here there is room to 
change the design ...).

- Objects in the third generation are collected by a reference counter + 
a specific GC: the counter counts the number of processes
holding at least one pointer to this object from their own stack, major 
or minor heap. This counter is only increased/decreased by the GC of 
each process
(a mutex is neeeded here). There is also a specific GC process (mark and 
sweep ?). To take care of pointers from the third generation to the 
third generation
and make sure that object with a zero counter can be removed.

- This third generation could be dealf with be a daemon and accessible 
by processes written using different languages ...

What do you think ?

 
-- 

Christophe Raffalli
Universite de Savoie
Batiment Le Chablais, bureau 21
73376 Le Bourget-du-Lac Cedex

tel: (33) 4 79 75 81 03
fax: (33) 4 79 75 87 42
mail: Christophe.Raffalli@univ-savoie.fr
www: http://www.lama.univ-savoie.fr/~RAFFALLI
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