3½-inch floppy disk

Lore & Background

The 3½-inch floppy disk was introduced in 1983 by many manufacturers, based on a variant of a Sony design. It featured a rigid plastic case with a sliding metal (or later, sometimes plastic) shutter over the head slot, which protected the delicate magnetic medium from dust and damage. A sliding write-protection tab replaced the adhesive tabs used on earlier disks. The format rapidly gained adoption, and by 1988 it was outselling the 5¼-inch format. By the mid-1990s, 5¼-inch drives had virtually disappeared, and the 3½-inch disk became the dominant format. Apple's later 1.44 MB high-density 3½-inch drives (marketed as the SuperDrive) could read, write, and format IBM PC–compatible floppy disks, but few IBM-compatible computers could read or write Apple-formatted floppy disks due to the disk controller's lack of support for Apple's GCR encoding used on 400 kB and 800 kB Macintosh disks.

Reader's Guide

The 3½-inch floppy disk was a ubiquitous form of data storage and data transfer into the first years of the 21st century. Its advantages over the 5¼-inch format—higher capacity, smaller physical size, and a rigid case providing better protection from dirt and other environmental risks—led to its widespread adoption. During the transition period, PCs frequently came equipped with drives of both sizes. The 3½-inch disk's success was such that it became the dominant format by the mid-1990s, and its iconic shape persisted in skeuomorphic design, with many electronic and software programs continuing to use save icons that look like floppy disks well into the 21st century. 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floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity and speed, such as USB flash drives, memory cards, optical discs, and storage available through local computer networks and cloud storage.

Did You Know?

• The 3½-inch floppy disk's rigid case included a sliding metal shutter over the head slot for protection.
• By 1988, the 3½-inch format was outselling the 5¼-inch format.
• Apple's SuperDrive could read, write, and format IBM PC–compatible 3½-inch floppy disks.
• The 3½-inch disk's sliding write-protection tab was more convenient than the adhesive tabs used on earlier disks.