I have sequentially up-graded to 8.10 and I didn't notice fd0 was gone
until after the most recent upgrade although it was there while I was
operating 8.04.

How do I get fd0 back? Bios knows it is there and I can boot into DOS
using a floppy boot disk.

I have also looked into the case and inspected power and data cables,
AOK.

Linux obviously can't find the drive to mount it.

I have many uses for a working floppy drive including lots of photos
and other data. It worked once and I want to restore it. If
necessary I can borrow a drive from another computer but I really
don't think it is a bad drive, although it is not a TEAC which is the
brand with which I have most experience.