Diskettes

Diskettes, commonly known as floppy disks, are removable magnetic storage media used in computers from the 1970s through the early 2000s. A diskette consists of a thin flexible plastic disk coated with magnetic oxide, sealed inside a protective plastic shell. Data is stored as magnetic transitions on the surface and read by a read/write head inside a disk drive. Many diskettes include a write-protect notch to prevent accidental data revision.

The major sizes were 8-inch, 5.25-inch, and 3.5-inch. The 8-inch disks appeared in the 1970s and could carry up to about 1.2 MB in double-sided, double-density formats, though they were large and gradually fell out of favor. The 5.25-inch format began in the mid to late 1970s, with capacities ranging from around 110 KB to 360 KB, then 720 KB, and up to about 1.2 MB in high-density versions. The 3.5-inch format, introduced in the 1980s, became dominant in the 1990s, standardizing at 1.44 MB for high-density disks, with 720 KB versions also common in earlier or alternative systems. Disks could be single or double-sided and formatted in different densities depending on the drive and system.

Use and formats: Diskettes were used to store and transfer software, documents, and backups. They required formatting for a given file system, and many personal computers designated the A: drive for floppy access. The write-protect notch allowed protection against accidental writes.

Decline and legacy: Floppy drives were largely supplanted by optical discs, USB flash drives, and networked storage in the late 1990s and 2000s. They remain of historical importance for early computing and digital preservation. Preservation efforts use specialized hardware or USB adapters to read old disks and migrate data to modern formats.