floppy disk (redirected from 5.25" Floppy disk)

floppy disk

 or diskette

Magnetic storage medium used with computers. Floppy disks are made of flexible plastic coated with a magnetic material, and are enclosed in a hard plastic case. They are typically 3.5 in. (9 cm) in diameter. Data are arranged on their surfaces in concentric tracks. A disk is inserted in the computer's floppy disk drive, an assembly of magnetic heads and a mechanical device for rotating the disk for reading or writing purposes. A small electromagnet, called a magnetic head, writes a binary digit (1 or 0) onto the disk by magnetizing a tiny spot on the disk in different directions, and reads digits by detecting the magnetization direction of the spots. With the increasing use of e-mail attachments and other means to transfer files from computer to computer, the use of floppy disks has waned, though they are still widely used to keep second (backup) copies of valuable files.

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floppy disk

A reusable magnetic storage medium and drive introduced by IBM in 1971. It was officially called a "diskette," but nicknamed "floppy," because the first varieties were housed in bendable jackets. Until the early 1990s, the floppy was the primary method for distributing applications, for backup and for transferring data between machines, and most all computers had a floppy drive. By the mid-1990s, the floppy gave way to the CD-ROM for software distribution, while local networks and the Internet became popular for backup and data exchange.

Like Magnetic Tape
The floppy's recording surface is a circular platter of magnetically coated plastic similar to magnetic tape, except that both sides are recordable. The drive grabs and spins the platter inside its jacket, while the read/write head contacts the surface through an opening in the jacket. At 300 RPM, floppies rotate considerably slower than a hard disk, and they also come to a complete stop when there is no read/write activity.

Format Before Writing
Every new floppy must be "formatted," which writes the sectors on the disk that hold the data (see format program). However, by looking at the external jacket, one cannot always discern the recording format. See magnetic disk and high-capacity floppy.

 FLOPPY TYPES (most recent to oldest)

                 Storage Capacity
 Jacket          Highest  Lowest  Creator

 3.5" rigid      1.44MB   400KB   Sony

 5.25" flexible  1.2MB    100KB   Shugart

 8" flexible     1.2MB    100KB   IBM

The Common Floppy Versions

Although ubiquitous in the late 1970s and early 1980s, the bendable 5.25" floppy was surpassed by the rigid 3.5" floppy in the late 1980s.

Anatomy of a 3.5" Floppy

The magnetic disk rotates between two liners inside the plastic jacket.

A Floppy-Based Computer

Floppy-based computers such as this Kaypro portable were the rage in the early 1980s. The computer was booted with the operating system floppy in the first drive, and the second drive was used for the application floppy.

Handwriting on the Wall

This 1999 headline foretold the floppy's future. Their value as a storage medium today is nil. (Article headline courtesy of the Philadelphia Inquirer.)

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floppy disk

a flexible removable magnetic disk that stores information and can be used to store data for use in a microprocessor

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floppy disk [¦fläp·ē ′disk]

(computer science)

A flexible plastic disk coated with magnetic oxide and used for data entry to a computer; a slot in its protective envelope or housing, which remains stationary while the disk rotates, exposes the track positions for the magnetic read/write head of the drive unit. Also known as diskette.

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(hardware, storage)

floppy disk - (Or "floppy", "diskette") A small, portable plastic disk coated in a magnetisable substance used for storing computer data, readable by a computer with a floppy disk drive. The physical size of disks has shrunk from the early 8 inch, to 5 1/4 inch ("minifloppy") to 3 1/2 inch ("microfloppy") while the data capacity has risen. These disks are known as "floppy" disks (or diskettes) because the disk is flexible and the read/write head is in physical contact with the surface of the disk in contrast to "hard disks" (or winchesters) which are rigid and rely on a small fixed gap between the disk surface and the heads. Floppies may be either single-sided or double-sided. 3.5 inch floppies are less floppy than the larger disks because they come in a stiff plastic "envelope" or case, hence the alternative names "stiffy" or "crunchy" sometimes used to distinguish them from the floppier kind. The following formats are used on IBM PCs and elsewhere: Capacity Density Width 360K double 5.25" 720K double 3.5" 1.2M high 5.25" 1.44M high 3.5" Double denisty and high density are usually abbreviated DD and HD. HD 3.5 inch disks have a second hole in the envelope and an overlapping "HD" logo.