Another name for a bootable diskette, a floppy disk (or CD-ROM) that a computer can use to boot the operating system (OS) if the hard drive fails to boot the OS. Typically, PCs will read the floppy disk drive before the hard drive when booting, so if the user leaves a floppy disk in the drive that does not contain the operating system or another control program, the computer will display a system disk error. The user can change the system BIOS so that the hard drive is read before the floppy drive.
