8.5 inch

A floppy disk or floppy diskette (sometimes casually referred to as a floppy or diskette) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure with a lined with a fabric that removes dust particles from the spinning disk. Floppy disks are read from and written to by a floppy disk drive (FDD).
The first floppy disks, invented and made by IBM, had a disk diameter of 8 inches (203 mm). Subsequently 5 1⁄4-inch (133 mm) and then 3 1⁄2 inch (90 mm) became a ubiquitous form of data storage and transfer into the first years of the 21st century. By 2006, computers were rarely manufactured with installed floppy disk drives; 3 1⁄2-inch floppy disks can still be used with an external USB floppy disk drive. USB drives for 5 1⁄4-inch, 8-inch, and non-standard floppy disks are rare to non-existent. Some individuals and organizations continue to use older equipment to read or transfer data from floppy disks.
Floppy disks were so common in late 20th-century culture that many electronic and software programs continued to use save icons that look like floppy disks well into the 21st century, which is often cited as an example of skeuomorphism in user interface 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floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater data storage capacity and data transfer speed, such as USB flash drives, memory cards, optical discs, and storage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.

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