I don't know what prompted the response below to a problem I had just 4 months
ago. The problem was solved, sort of, as described in messages 13699 and my
response 13702.

For the present, I have upgraded to 9.04 and my floppy was preserved as in the
past. I suspect my problem was caused by 8.10.

I have not been trying to format any floppies so can't report my progress in
that area.

Thanks again for those who gave me their advice.