Bob Rogers wrote:

>  So that means you do not use the IGP pointer to A when collecting any
>  generation <= j, correct?  Otherwise, I imagine you'd always decide that
>  A is alive, and hence B and C.

IGPs entries that span the range of to be collected generations are not 
considered (and very likely removed)

>     But what if A, B, and C are all in the same generation?  You'd still
>  need an IGP entry, even though it's not inter-generational, in order to
>  handle the backpointer, but how would you then decide that it's invalid?

I don't think this needs an IGP entry. Just a bit POSSIBLE_LOOP, which 
prevents early collection of dead objects during the sweep.

>   ...  Perhaps you should save your (metaphorical) breath, and I'll
>  wait for a more detailed design.

I'm waiting too :-)

>  					-- Bob Rogers

leo