submemories and grouping objects (was: Re: Islands up and running)

Michael van der Gulik mikevdg at hetnet.nl
Mon Jul 7 21:26:45 UTC 2003


Mmm.. yummy. I'll be sinking my teeth into that tommorrow!

Lex (or others) - I have a question. You mention 'submemories' at the 
end of that document about Islands, referenced below. Has anybody ever 
tried anything like this?

I'm currently working on my master's project about replicating objects 
(dpon.sourceforge.net). My current problem is how to increase the 
'granularity' - replicating a single object is just too inefficient 
because objects are small; on the order of a few dozen bytes. A way to 
do this is to use 'submemories', 'segments', 'object groups' or whatever 
you would like to call them, to group related objects together and 
replicate them as a block. Kind of like what ImageSegments do.

The way I see it, there are two ways of attacking this - the hard way 
and the soft way. The soft way is by putting your hand into the goop of 
objects and pulling a handful of inter-related objects out. That would 
then be your segment. You can then do goopy things with object goop, 
like splitting it in two, or merging it with another goop, or throw it 
back in the pool of goop. You would catch messages going to that goop 
and use them to replicate the objects in that segment.

The hard way would be to make hard segments - define objects to 
explicitely be owned by another. Then you have a sort of ownership 
hierarchy, with owner objects acting as Interfaces (or 
SegmentManager's?) to a segment. This is nice because you can do 
security stuff and management stuff. Security stuff would be like not 
allowing objects 'private' to a segment to be referenced from outside 
(an extra layer of protection above capabilities), and perhaps vice 
versa. Management stuff would be like you say - this segment is only 
allowed to use so much memory, and so much CPU time and below a 
particular priority etc. There are also a lot more possibilities. 
Essentually it would let you make lots of mini-VM's that are completely 
isolated (except for an interface to the outside world) from the rest of 
Squeak.

Sorry; this has got a bit long. My question was: "Has anybody ever done 
anything related to grouping objects together?".

Michael.

Lex Spoon wrote:
> If anyone wants to play with Islands, it's much easier now.  
> 
> Download everything from:
> 
> 	http://minnow.cc.gatech.edu/squeak/2074




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