A floppy-disk controller (FDC) is a hardware component that directs and controls reading from and writing to a computer's floppy disk drive (FDD). It has evolved from a discrete set of components on one or more circuit boards to a special-purpose integrated circuit or a component thereof. An FDC is responsible for reading data presented from the host computer and converting it to the drive's on-disk format using one of a number of encoding schemes, like FM encoding or MFM encoding, and reading those formats and returning it to its original binary values.
FDC board from an IBM 5150. The NEC D765AC FDC IC is the large dual in-line package at the top.
Block diagram showing FDC communication with the CPU and the FDD.
A setup disk of Japanese Microsoft Office 4.3, provided with 3.5" 1.2 MB and 1440 KB formats.
A floppy disk or floppy diskette is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a fabric that removes dust particles from the spinning disk. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device.
8-inch, 5¼-inch, and 3½-inch floppy disks
8-inch, 5¼-inch (full height), and 3½-inch drives
A 3½-inch floppy disk removed from its housing
8-inch floppy disk, inserted in drive, (3½-inch floppy diskette, in front, shown for scale)
