Floppy Disks
Floppy Disks are removable memories that appeared in 1971, firstly made by IBM. They consist of a magnetic disk packaged in a flat plastic case.
The disks firstly had a diameter of 8 inches (20.32 cm) and could store up to a few hundreds kB of data. The size was later reduced to 5.25" (13.335 cm) and 3.5" (8.89 cm). Most floppy disks of the latter size are designed to store 1.44 MB of data, though there were also more uncommon formats, notably the double density version storing 2.88 MB.
Floppy disks were ubiquitous during the 1980s and 1990s, but the appearance of optical disks and flash drives that are more reliable and able to store much more data made them obsolete and progressively disappear during the 2000s.