No, not fragmented files - I'm not going to tell you to defrag your computer! I keep a fragment file; it contains all the little bits of stuff I want to write about but haven't fitted into a story yet like:
1 the line of conversation I overhead at a wildlife park 'So they're all having fish except the polecats and they get fish-heads, right?' - irresistible, even if I don't quite know what to do with it yet.
2 the fact that Inuit and Himalayan peoples have the same creation myth - there's got to be a science fiction super-race story in that somewhere.
3 the death certificates of girls who worked in match factories before the first war and died of 'fossy jaw'; cancer of the bone caused by phosphorus in matches.
When I can't think of anything to write, I pull out that file and start going through it. I never get to the end because something always triggers the urge to write.
It also contains fragments that I have removed from stories. Lovely lines of prose or beautiful descriptions that I don't want to lose, but that didn't fit with the final version of the story, or wouldnt' have been right for the publication I was aiming at. I've never used one of those edited baubles again, but knowing there's a place I can keep them safe makes it easier for me to cut them from my final version. Publication requires ruthlessness from the writer, and alhtough it hurts to cut the words I think are the best or the most beautiful, I have learned to accept that if I want to be published, I have to be tough on beauty if it doesn't fit the piece.