Re: robustness vs. conservative GC

[Tom Lord <lord at regexps dot com>]

       On Fri, 10 Aug 2001, Tom Lord wrote:
       > You push in here and it pops out there.  This design would seem to to
       > raise the probability of incorrectly failing to collect some genuinely
       > dead objects, which is an unpredictable and uncontrollable source of
       > arbitrarilly catastrophic failure, sufficiently improbable to escape
       > most testing, and sufficiently serious that it ought not be ignored or
       > swept under the rug with vague (and inaccurate) replies such as "the
       > resulting leaks only waste a little memory" (a specific reply I do not
       > attribute to Hans).

       Supposing you do have exact type information for the stack, how can GC 
       be certain a stack slot is initialized?

If the information you have doesn't tell you that, then it isn't
exact.


	> That's misleading.  One practical question is whether the programmer
	> has useful pre-conditions that assure an object has been collected.
	> Keeping track of object references isn't "hard to predict" for all
	> objects;  on the contrary -- it's part of how good programmers use
	> good collectors.

	Your argument makes sense only for resources that are used by a
	single thread.  

Nonsense.

-t