原文(source): Create Floppy Disk Images from within Linux | LegRoom.net.
In order to create floppy disk images, you'll need a copy of dosfstools installed. It should be available in most package repositories. Once installed, the following command does all the magic:
mkfs.vfat -C "floppy.img" 1440
You now have an empty, but valid, floppy disk image. In order to copy files to the image, you need to mount the image using the loop device:
sudo mount -o loop,uid=$UID -t vfat floppy.img /mnt/floppy