> From: Stephen Pair [mailto:spair at advantive.com]
> Subject: Adding a word to Squeak's object header
[...]
> I'm not familiar enough with the VM code to know what kind of snafus I
> should be looking for.  I'm hoping someone who's been there 
> and done it before might have some tips.

I last tried to attack this on one of Tim's modified 2.3 systems.  The main
thing to watch out for is the garbage collector, which does strange and
terrible things to your object memory when you least expect it.  Make sure
you've modified the GC appropriately, or the first incremental GC will
really ruin your day.  To (probably mis-)quote Dan, "Trying to study objects
in a garbage-collecting VM is like trying to study frogs using a blender."

The main problem I had was how to identify objects that had the extra word,
because I didn't want to add it to every object --- you'll have a much
easier job if you're happy to add a word to every header.

		- Peter