[gclist] Memory cheats and VM (was Counting on one thumb)

[David Chase]

Two things to note:

1. This stuff has been studied before in other contexts; there's 
Stoye's 1-bit hardware reference counts, for instance, and the SETL 
project produced a number of papers on analysis and optimization 
of copying and reference-counting.  If I had the time, I'd yank the 
relevant stuff out of my bibliography, but I don't have time today. 
It would be good to avoid re-inventing the wheel, and it would be 
good to measure things.  The point about blindly copying anything 
statically known to be small is a good one (with the obvious inference 
that the relative costs and frequencies of sharing versus copying 
could be measured and tuned, on a size and/or type-specific basis, 
and that this would probably also vary depending on the machine where 
it was done). 

2. I'll be changing my address, "chase@naturalbridge.com" will do
for now.  I'll see about relocating the GC FAQ page to someplace 
else, and then post when I do that.  As usual, if anyone has any
comments on content, I'm happy to listen.  It's been a pretty busy
couple of months, and I've let it slide, and the next few months 
will be just as busy.

David Chase
CenterLine Software (today)
Natural Bridge (tomorrow)