Hmmm, actually, I think something like this was implemented in a recent patch to DROD. How recently did you download the game?
Two copies of the dat files should be saved, and if upon starting DROD one of them gets corrupted, the previous version will be loaded up. So you might lose some progress but at least you won't lose all of it.
If this happens a lot it could be symptomatic of a larger problem. If your computer crashes a lot, quitting out after every room just to be safe could be a good idea, although it's not much fun.
Sorry it happened to you!
Game on,
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"
He who is certain he knows the ending of things when he is only beginning them is either extremely wise or extremely foolish; no matter which is true, he is certainly an
unhappy man, for he has put a knife in the heart of wonder."
-- Tad Williams