process checkpoint restore facility now in DragonFly BSD

[Sam Leffler]

I've lived through several checkpointing implementations.  You've got the easy 
part.  Applications must participate or such a facility has very limited 
usefulness.  Delivering a signal is only part of the problem; there tend to 
be issues synchronizing user-mode checkpoint of application state with the 
kernel's desired to stop the process and squirrel away state.

There's lots of stuff published about this; check the literature.

	Sam