What is the Bootable Floppy?
Many people do not know what is the bootable floppy, it is very simple.The bootable floppy is the diskette contained a back-up copy of your hard disk master boot record (MBR). When the master boot record becomes "infected" by the boot virus, if having a bootable floppy will allow you to load it back onto your hard disk. Otherwise, you must have to reformat your harddisk which first erases everything on the disk including files you may not have a backup copy of. Even if you do that will mean you need to restore everything you've backed up, it will lost much time to complete.
If you want to make a dos bootable floppy ,you should read this post:How to Make a Dos Bootable Floppy?