A couple garbage collector questions

[Douglas Alan]

I wrote:

> I have a couple of questions regarding the new Python garbage
> collector:

>   (1) Why does it use the rather unusual algorithm it does, rather
>       than a more typical mark and sweep?  The per-object storage cost
>       for the extra reference count is surely greater than the bit or
>       two required for a typical mark and sweep.

I thought of another potentially good reason for the GC algorithm used
by Python: The Python GC is generational, is it not?  With this
algorithm, supporting generational GC seems pretty darn
straight-forward.  But with a normal mark & sweep, supporting
generational GC involves keeping track of a "remembered set" of
references from outside the nursery.  Perhaps this is very easy to do,
but it seems to me as if it might be a kind of tricky.  Does anyone
know?

|>oug