Floppy drives dying, floppy discs going the way of the shaper,,,,you can fix it, and/or install a USB...
I just did that on our '99 4020, and while loading from the USB is different (and kinda weird because of the software interface), you're not limited by the file size of the floppy....
You can order direct from Fadal for over $800, or get it a lot cheaper at Calmotion
http://www.calmotion.com/usbcncfad.html
If I can do this, anybody can do this. But there are some caveats...
The "kit" is supposed to come with a 25' RS232 cable, but it don't. I got some shielded cable and a separate cable end and made my own. You'll have to cut and splice the cable back together anyway. I drilled a hole in the pendant and mounted the USB on the rear of the pendant, not the side by the floppy because I didn't like my thumb drive vulnerable to the isle traffic.
On the other end I ran the wire outside the main control box (after running the cable through the raceway from the pendant), re-attached the RS232 shell, and plugged it into the RS232 port. That way, if I need/want the regular RS232 port, I only need to unplug)
Power for the USB adapter is easy to find on the board inside the pendant.
It took me around 3 hours,,but I'm slow and was trying to be real careful, and ...I hadn't done it before. The factory guy would supposedly do it in an hour...I doubt it.
The software is built into the adapter and comes with a delightful instructional door magnet.
Sorry I can't help with the floppy issue, but I'd anticipated that one day it'd die and I'd need an alternative that had larger capacity, and was easy to run DNC.