History (1976): 5.25-Inch Minifloppy Disk

This article was published by the Museum of Obsolete Media.

5.25-inch minifloppy disk (1976-early 1990s)

The 5.25-inch floppy disk (or minifloppy) was a magnetic disk format introduced by Shugart Associates in 1976, as a replacement for the 8-inch floppy disk that was considered too large for newer desktop machines.

Like the 8-inch floppy, the 5.25-inch disk consisted of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removed dust particles.

Write protection was carried out by affixing an adhesive tab.

By 1978 a number of manufacturers were producing disks, in competing formats including hard and soft-sector versions, and different encoding schemes.

Initially, 5.25-inch disks had a capacity of 110KB, with a double-density disk introduced in 1978 with a capacity of 360KB, and quad-density introduced in the early 1980s with a capacity of 720KB.

In 1984, IBM introduced the high-density 1.2MB disk in its PC AT, but by the time of the launch of the PS/2 line in 1987 moved to 3.5-inch floppy disks, as Apple had already done with its Macintosh line in 1984.

By 1988 the 3.5-inch was outselling it, and by the mid-1990s the 5.25-inch disk had virtually disappeared, and there was no option to purchase Windows 95 on 5.25-inch disks.

All disks were coated on both sides whether single or double-sided, but only double-sided disks were certified error-free on both sides of the media. However, it was possible to use both sides of a single-sided disk in single-sided drives, by making or buying so-called ‘flippy’ disks.

More expensive dual-head drives which could read both sides of the disk without turning it over were later produced, and eventually became used universally.