Good point, Charlie, but isn't it largely a matter of size rather than
of design? Suppose you had an earth-mass of O'Neill cylinders. (How
many would that be? A whole lot, you betcha.) Now throwing a rock or
two isn't going to cause much damage either.
Conceivably the system could even withstand collapse of civilization,
if it is self-repairing. The idea of a culture living unknowingly within
a starship is as old as SF.
> Of course, why the hell are we talking about habitats to support an
> agriculture-based society when there's the open question of what kind
> of habitat is appropriate to an uploaded mind to discuss?)
In Greg Egan's Diaspora (now available in the U.S., BTW) a whole
civilization lives uploaded in a featureless blob a foot or so in size.
(Actually it was never clear to me how large the population was; at some
point I had the impression that everyone knew everyone else at least
dimly, and even accounting for large lifespans it would suggest that
there were no more than a few million inhabitants).
Hal