I'm trying to use a floppy disk in a i386 machine.

So, I formated with "fdformat" and created a MSDOS filesystem with 
"newfs_msdos -f 1440 /dev/rfd0a". Now I'm trying to boot:

# mount -t msdos /dev/fd0a tmp
mount_msdos: /dev/fd0a on /home/dbolgheroni/tmp: Inappropriate ioctl for 
device
# mount -t msdos /dev/rfd0a tmp
mount_msdos: /dev/rfd0a on /home/dbolgheroni/tmp: Block device required
#

I'm trying these two commands without success. What's wrong? What's the 
difference between /dev/fd0a and /dev/rfd0a?

Thank you in advance.