Recently, I’ve needed to create DOS floppy images to use with VMWare. Floppy images end up being more convenient than trying to set up LANMAN or other networking in DOS. I used to use dd(1), but it’s come to my attention that the mkfs.vfat(8) now has a -C option, that does some of that hard work for you.

mkfs.vfat -C "myfloppy.img" 1440
mount -o loop -t vfat ./myfloppy.img /mnt

Near as I can tell, these images work great with DOS 6.2. I’m not quite sure on earlier versions.