xanadu & forth
Thu, 28 Oct 1999 23:30:38 -0400 (EDT)
On Thu, 28 Oct 1999, Jecel Assumpcao Jr wrote:
> I don't think Xanadu allowed deletions at all. In my current
> design for my system, only transient objects are subject to
> garbage collection. Persistent object are not. I noticed that
> only a tiny amount of information in my disks was actually
> created by me (and I have 140MB of saved emails!!). The rest
> was created elsewhere and downloaded from CD-ROMs or over the
> internet. I could easily remove these "replicas" from my local
> disks and would in no way be deleting the objects from the world.
> If I focus on just my stuff, it is clear that it will grow much
> less than the amount of disk available even if I never throw
> anything out (and I buy less disk space than most people I know:
> I keep trying to make do with the old 120MB drives I have lying
> around instead of buying new ones). So, after struggling with
> distributed garbage collection for 14 years I just gave up and
> joined the Xanadu club: keep everything.
I noticed a parallel in Forth: when you create new words (ie, objects),
they just get piled onto the heap. If you redefine a word, the old
definition stays in memory. No garbage collection. You want to make
something temporary, don't mix it up with permanent stuff.
Just another indication that GC is nothing to worry about... don't write
garbage, and you won't need garbage collection :)