You'll need to use a disk image. Try using Disk Utility to make a 1440 KB disk image with no partition map and a FAT filesystem. Mount the disk image and copy your stuff onto it. Then use dd from the ...
A disk file that simulates a floppy disk. It is used to duplicate floppies, to boot a remote server from anywhere on the network as well as to simulate a floppy drive for old programs that require one ...