Sigh. I just hit something, and the notebook disappeared ... along with several hours of work. Is there someway to tell Mathematica to automatically save the notebook I am working in every 30 minutes (or so ...)?
Or how about a "unexpected exit ... recovery possible possible" function? That is, when Mathematica exits and leaves an un-saved notebook, the next time I run Mathematica, it tells me "You have an unsaved file. Do you want to recover it?" Other program do this sort of thing.
I'm running an old version of Mathematica .. Version 8.