A report on Floppy-disk controller and Group coded recording

5-1/4 Diskette Drive Adapter found on the IBM PC. This card is based on the NEC D765AC, the large chip at the top of the image.

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.

Translate data bits into FM, MFM, M²FM, or GCR format to be able to record them

- Floppy-disk controller

Offering GCR-compatible diskette drives and floppy disk controllers (like the 100163-51-8 and 100163-52-6 ), Micropolis endorsed data encoding with group coded recording on 5¼-inch 100 tpi 77-track diskette drives to store twelve 512-byte sectors per track since 1977 or 1978.

- Group coded recording

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Floppy disk

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Obsolete 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.

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)

3½-inch, high-density floppy diskettes with adhesive labels affixed

Imation USB floppy drive, model 01946: an external drive that accepts high-density disks

Front and rear of a retail 3½-inch and 5¼-inch floppy disk cleaning kit, as sold in Australia at retailer Big W, circa early 1990s

Different data storage media (Examples include: Flash drive, CD, Tape drive, and CompactFlash)

A floppy hardware emulator, same size as a 3½-inch drive, provides a USB interface to the user

Screenshot depicting a floppy disk as "save" icon

Disk notcher converts single-sided 5¼-inch diskettes to double-sided.

Rear side of a 3½-inch floppy disk in a transparent case, showing its internal parts

How the read-write head is applied on the floppy

Visualization of magnetic information on floppy disk (image recorded with CMOS-MagView)

A box of about 80 floppy disks together with one USB memory stick. The stick is capable of holding over 130 times as much data as the entire box of disks put together.

There were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as differential Manchester encoding (DM), modified frequency modulation (MFM), M2FM and group coded recording (GCR).

Hardware floppy disk emulators can be made to interface floppy-disk controllers to a USB port that can be used for flash drives.