"A floppy disk is a data storage medium that is composed of a disk of thin, flexible ("floppy") magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which is another term for a (nonremovable type of) hard disk drive. Invented by IBM, floppy disks in 8-inch (200 mm), 5¼-inch (133.35 mm), and 3½-inch (90 mm) formats enjoyed many years as a popular and ubiquitous form of data storage and exchange, from the mid-1970s to the late 1990s. While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment,[2] they have now been largely superseded by USB flash drives, External Hard Drives, CDs, DVDs, and memory cards (such as Secure Digital)." - jho

"For quite a while in the 1980s, users could purchase a special tool called a disk notcher which would allow them to cut a second write-unprotect notch in these diskettes and thus use them as "flippies" (either inserted as intended or upside down): both sides could now be written on and thereby the data storage capacity was doubled. Other users made do with a steady hand and a hole punch or scissors. For re-protecting a disk side, one would simply place a piece of opaque tape over the notch or hole in question. These "flippy disk procedures" were followed by owners of practically every home-computer single sided disk drives. Proper disk labels became quite important for such users. Flippies were eventually adopted by some manufacturers, with a few programs being sold in this medium (they were also widely used for software distribution on systems that could be used with both 40 track and 80 track drives but lacked the software to read a 40 track disk in an 80 track drive). The practice eventually faded with the increased use of double-sided drives capable of accessing both sides of the disk without the need for flipping." - jho

i think i remember those, ;) - chaz2b