From: "Mauricio Fernández" <batsman.geo@...>
Date: 2002-08-24T09:40:03+09:00
Subject: [OT] Re: Why Ruby Uses Mark-and-Sweep GC?

On Sat, Aug 24, 2002 at 03:27:58AM +0900, Dan Sugalski wrote:
> At 3:18 AM +0900 8/24/02, Perry E. Metzger wrote:
> >Dan Sugalski <dan@sidhe.org> writes:
> >> At 1:18 AM +0900 8/24/02, William Djaja Tjokroaminata wrote:
> >> >I think one of the problems with reference counting is the circular
> >> >reference, which cannot be handled by the gc.
> >>
> >> That's one problem. Reference counting is also more expensive over
> >> the long run than more automatic methods. Also more error-prone.
> >
> >There are, of course, better gc's than mark and sweep -- compacting
> >collectors and generational compacting collectors come to
> >mind. Writing an implementation that deals with a compacting collector
> >can be a royal pain though -- you never know when an object will get
> >moved out from under you.
> 
> Believe me, I'm well aware of that pain. :(
> 
> When dealing with external libraries, a pure copying collector's not 
> an option--Oracle, for example, would *really* hate it if you screwed 
> around in its internals changing references to things.
> 
> The practical alternative is to have moveable and nonmoveable parts 
> of objects, and a mechanism to pin objects so they temporarily don't 
> move. It's what we've done with Parrot. Not the only solution, but an 
> adequate one under the circumstances.

Is Parrot's convoluted copying GC generational?

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