Image Segments (was: RE: Swiki.net vs. Comanche ?)

Stephen Pair spair at advantive.com
Wed Nov 1 12:43:23 UTC 2000


> I am coming from a background in Zope. With Zope you have a
> sophisticated permission system which allows the owner/creator/manager
> of an object the capacity to determine who is able to do what with the
> object...

Yes, this is very similar to what we do in Swiki.net

> I thought I saw something about image segments. Is there any information
> about that anywhere? I've tried to search the egroups archives but
> searching for "image" and "segments" isn't easy. :(

I can't point you to anything directly (other than the image itself).
Perhaps Dan has a good description of them.

> I thought (maybe naively so) that if image segments were possible that
> they would make for a great basis of an OODB. Reasoning that they are
> the native objects system of Squeak. If multiple Squeak image segments
> were usable from a master Squeak (and image) then one could partition
> apps and data into their own image segment. Just some thoughts. I may be
> late to this party. :)

I believe they can be the basis for a great OODB...however, the last time I
looked, image segments specified a system of objects by identifying a set of
"root objects" and then using the garbage collector to find all objects in
the shadow of those roots.  This is fine for certain applications, however,
it is probably too slow for a database full of a bunch of really small ones.
What's needed is a way of specifying the set of objects to go in an image
segment in a more declarative way, avoiding the need to use GC...maybe this
has been added recently?  I don't think it should be too hard to do and
would be really useful.

- Stephen





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