Garbage collection for files (was Re: More on Hard Links (was A bold idea (Re: Carrying Attributes too Far)))

[David Masover <jedi@ninja.dynup.net>]

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I will step aside and let the smart people figure this out.  Only one 
real suggestion -- most directories will not have loops.  I'm not sure 
how, but I'd imagine it's possible to use refcounts there and other 
forms of garbage collection elsewhere.  I felt my refcount-based idea 
was clean and cool-looking, but I have had approximately 10-15 mins of 
experience in this subject.

Only one question -- does it work for rm -rf?

Thread below:

Nikita Danilov wrote:

>Hans Reiser writes:
> > Nikita Danilov wrote:
> > 
> > > But if multiple hard-links to the directories
> > >are allowed, file system is an arbitrary graph. It makes little sense to
> > >try to stretch reference counting to work in this situation. There are
> > >much more efficient forms of garbage collection for this.
> > >
> > >Nikita.
> > >
> > >
> > >  
> > >
> > Educate us, I am curious.
>
>http://citeseer.nj.nec.com/jones03garbage.html is a recent bibliography
>in this subject, containing more than 20000 references. I am afraid this
>is little too much for a brief description. But basically, instead of
>reclaiming garbage when "last reference" goes out, collectors typically
>run periodically trying to find unreachable objects. Common way to do so
>is to find -reachable- ones, and then to declare the rest
>unreachable. Also, do avoid scanning the whole heap^Wfile system,
>objects are segregated into "generations", and allocation is tuned so
>that there are no references from object older generation to younger
>one. Some smart techniques (like colored pointers) are used to avoid
>garbage collection to proceed concurrently with mutators. And so
>on. Large field for an experimentation.
>
> > 
> > -- 
> > Hans
> > 
>
>Nikita.
>
> > 
>  
>

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