Floppy disk
A magnetic storage medium enclosed in a square plastic shell.
A floppy disk—also called a diskette—is a data storage device built around a thin, flexible magnetic disk. This disk sits inside a square or nearly square plastic shell lined with fabric that cleans dust off the disk as it spins. To read or write digital data, you insert the disk into a floppy disk drive (FDD), which may be built into a computer or connected externally. The three most common sizes of floppy disks and their drives are 8-inch, 5¼-inch, and 3½-inch.
IBM created the first floppy disks in 1971, with an 8-inch diameter. Later came the 5¼-inch (130 mm) and then the 3½-inch (90 mm) versions, which became widespread for storing and moving data into the early 2000s. By the late 1980s, 5¼-inch disks had been replaced by 3½-inch disks, and many PCs of that era included drives for both sizes. By the mid-1990s, 5¼-inch drives were nearly gone, and the 3½-inch disk ruled. Its advantages were higher capacity, a smaller size, and a rigid case that shielded the disk from dirt and other hazards.
Floppy disks were so common in late-20th-century culture that many software programs still use a floppy-disk icon for the save function, a skeuomorphic design choice that persists into the 21st century. Though floppy drives still see limited use—especially with older industrial equipment—they have been overtaken by faster, higher-capacity storage like USB flash drives, memory cards, optical discs, and network or cloud storage.
Industry observers group floppy disks and drives into four main categories by size and capacity: 8-inch, 5.25-inch, 3.5-inch, and high-capacity floppy disks. There were also variants that didn't fit these categories. The key difference between high-capacity products and standard floppies was the use of servomechanisms to increase the number of tracks and thus capacity. Each category represented a generation; each new generation had greater market success and replaced the previous one. However, the high-capacity generation, while somewhat successful, never matched the 3½-inch generation's popularity and was essentially obsolete by 2011.
The original IBM 8-inch disk was exactly 8 inches, but other sizes are defined in millimeters, with their names being rough approximations. Disks of different sizes are mechanically incompatible—each fits only its own drive.
- First commercial floppy disk diameter
- 8 in
- Year first floppy disks invented and mad
- 1971
- Most common capacity of 5.25 in format i
- 360 KB (368,640 bytes) for Double-Sided Double-Density (DSDD) format using MFM encoding
- Capacity of ibm pc/at 5.25 in floppy dis
- 1.2 MB (1,228,800 bytes)
- Capacity of ibm 3740 diskette 1
- 242,944 bytes
- Year 3.5 in outsold 5.25 in
- 1988
- Year high-capacity floppy generation bec
- 2011
Lore & Background
The first floppy disks, invented and made by IBM in 1971, had a disk diameter of 8 in. Subsequently, the 5¼-inch (130 mm) and then the 3½-inch (90 mm) became a ubiquitous form of data storage and data transfer into the first years of the 21st century. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks. During this time, PCs frequently came equipped with drives of both sizes. By the mid-1990s, 5¼-inch drives had virtually disappeared, the 3½-inch disk became the dominant format. The advantages of the 3½-inch disk were its higher capacity, smaller physical size, and its rigid case which provided better protection from dirt and other environmental risks.
Industry observers categorize floppy disks and floppy disk drives according to size and capacity with four major categories being 8 in, 5.25 in, 3.5 in and high-capacity floppy disks and floppy disk drives. The distinguishing characteristic between the high-capacity products and their lower capacity brethren, frequently categorized as standard floppies, was the use of servomechanisms to increase the number of tracks and thereby increase capacity. The four categories each represented generations; from the beginning each generation had substantially greater market success and ultimately succeeded the previous one, but the high-capacity floppy generation, although having some success, was never as successful as the prior 3½-inch generation, and became essentially obsolete by 2011.
Different sizes of floppy disks are mechanically incompatible, and disks can fit only one size of drive. Drive assemblies with both 3.5 in and 5.25 in slots were available during the transition period between the sizes, but they contained two separate drive mechanisms. As computer platforms began to form, attempts were made at interchangeability. Apple's later 1.44 MB high-density 3.5 in drives (marketed as the SuperDrive) could read, write, and format IBM PC–compatible floppy disks. However, few IBM-compatible computers were able to read or write Apple-formatted floppy disks. The limitation was due not to the 3.5 in drive mechanism itself, but to the disk controller and its lack of support for Apple's GCR encoding used on 400 kB and 800 kB Macintosh disks.
Reader's Guide
Floppy disks were so common in late 20th-century culture that many electronic and software programs continue to use save icons that look like floppy disks well into the 21st century, as a form of skeuomorphic design. While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater data storage capacity and data transfer speed, such as USB flash drives, memory cards, optical discs, and storage available through local computer networks and cloud storage. The 8-inch, 5.25-inch, and 3.5-inch formats each represented a generation that substantially succeeded the previous one in market success. The 3.5-inch format became the dominant format by the mid-1990s, but even it was eventually overtaken by higher-capacity and faster storage technologies. The high-capacity floppy generation, though having some success, never matched the market penetration of the 3.5-inch generation and became essentially obsolete by 2011. The floppy disk's legacy endures primarily in the skeuomorphic save icon and in niche industrial applications.
Did You Know?
- The most common capacity of the 5.25 in format in DOS-based PCs was 360 KB for the Double-Sided Double-Density (DSDD) format using MFM encoding.
- By 1988, the 3.5 in floppy disk was outselling the 5.25 in format.
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