floppy disk (redirected from 3.5" inch floppy drive)

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 introduced by IBM in 1971. It was called a floppy because the first varieties were housed in bendable jackets. Woefully undersized for today's use, it is no longer standard equipment on computers. However, until the early 1990s, the floppy was the primary method for distributing software and was widely used for backup. By the mid-1990s, it had mostly given way to the CD-ROM.

A Circle of Double-Sided Magnetic Tape
Also called a "diskette," the floppy is a flexible circle of magnetic material similar to magnetic tape, except that both sides are used. The drive grabs the floppy's center and spins it inside its housing. The read/write head contacts the surface through an opening in the plastic shell or envelope. Floppies rotate at 300 RPM, which is from 10 to 30 times slower than a hard disk. They are also at rest until a data transfer is requested. Following are the three types developed, from newest to oldest, and their raw, uncompressed storage capacity.

                 Final
                 Storage
 Housing         Capacity   Capacity Range  Creator

 3.5" rigid      1.44MB     400KB - 1.44MB  Sony
 3.5" rigid      2.88MB     (See ED.)       IBM
 5.25" flexible  1.2MB      100KB - 1.2MB   Shugart
 8" flexible     500KB      100 - 500KB     IBM

Although floppy disks look the same, what is recorded on them determines their capacity and compatibility. Every new floppy must be "formatted," which records the sectors on the disk that hold the data. See format program, magnetic disk and high-capacity floppy.

Floppy Formats

Although ubiquitous in their heyday, the 5.25" diskette was surpassed by the 3.5" disk in the 1980s, which gave way to the CD-ROM in the 1990s.

Anatomy of a Floppy

There is quite a bit inside a floppy disk considering they can be purchased for less than a quarter.

A Floppy-Based Computer

Floppy-based computers such as this Kaypro portable were the rage in the late 1970s and early 1980s. You typically booted the computer with the operating system in the first drive and saved your data on the floppy in the second one.

The Handwriting on the Wall

This 1999 headline foretold the floppy's future. Their value as a storage and distribution 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.