Well, they don't. And more generally, restoring the original session state, whether after a "hot exit" or not, is not really possible. Processes are bound to a

Well, they don't. And more generally, restoring the original session state, whether after a "hot exit" or not, is not really possible. Processes are bound to a running OS. Shutting down causes closed file descriptors, broken TCP connections, and what not. No matter how much effort you are willing to put into restoring a session, it will be unreliable at best.