first floppy drive = floppy0 = /dev/fd0
second floopy drive = floppy1 = /dev/fd1

double sided high density 3.5 inch disk  =  /dev/fd0H1440

to format
    $ fdformat /dev/fd0H1440

Note : NOT MOUNTED

before you can mount the floppy and after you format it you must add a filesystem.
    $ mkfs -t ext2 /dev/fd0

now you can mount and use the floppy.