This page shows how to dump and image 3.5" and 5.25" MS-DOS/Windows floppies. The examples all use dd and ddrescue, and were tested on Linux machines only. Please note that due to the nature of the medium, successive reads from a damaged area may exacerbate the damage.
(All commands were done on a computer with a regular 3.5" floppy drive hooked up thru IDE, not a USB drive).
At the most basic level, to view the files, and do basic operations on a disk, try mtools. Here is documentation on using it- the page is old, but it contains the essentials about mtools.
Basic image using DD:
dd if=/dev/fd0 of=AOL25-test.img conv=notrunc The most basic attempt at making an image- it stops when it hits an error.
Imaging a disk with one or more errors on it:
ddrescue -d -n -b512 /dev/fd0 Lemmings.img Lemmings1 This attempts to image a floppy, continuing when it hits an error, and leaving notes in a log file where the gaps are.
Using split functionality to recover additional data from disk:
ddrescue -d -b512 /dev/fd0 Odell-Down-Under-disk2-copy.img Odell2 This allows ddrescue to split the damaged areas, and then tries to recover data from each new range.
Telling ddrescue to try again from scratch:
ddrescue -d --retrim -b512 /dev/fd0 Sea-Rogue-disk3.img Sea-Rogue3
A very powerful ddrescue imaging attempt:
ddrescue -d --retrim -r 3 -b512 /dev/fd0 Sea-Rogue-disk3.img Sea-Rogue3 Try from scratch again, reading in reverse this time, with 3 tries for each error.