FLOPPY DISKS

3.5″ 1.44 Mb

The 3.5-inch floppy disks (about 90 mm side), also known as "micro floppy disks", also familiarly called "microfloppy", were the result of a further evolution of the original 8-inch floppy disks, invented and initially released by Shugart and Wang Laboratories. Despite the name and unlike the 8 and 5.25 inch floppy disks, they had a hard shell rather than a flexible one. In addition, the magnetizable disc had been equipped, instead of the central hole, with a metal pin to facilitate traction. A metal spring cover was also introduced to protect, when not inserted in the drive, the uncovered area of ​​the protection (previously this area was always exposed, forcing users to keep the disc in special covers when not in use). Finally, to prevent the drive from writing operations, a mechanism was inserted to discover, when necessary, the appropriate signaling hole (previously the hole had to be covered with adhesive tape, and the message sent to the drive was reversed: hole covered indicated forbidden writing, while open hole allowed writing).

5″ ¼ 1.6 Mb

5.25-inch floppy disks (over 13 cm per side), also called "mini floppy disks", also known as "minifloppy", are the result of an evolution of the original 8-inch floppy disks, invented and spread initially by Shugart and Wang Laboratories.

8″ 1.2 Mb

I floppy disk nacquero nel 1967 quando l’ingegnere fisico Alan Shugart, che nell’IBM ricopriva il ruolo di Direct Access Storage Product Manager, mise a punto un sistema semplice e poco costoso per caricare microcodice sui suoi mainframe System/370. Il risultato fu un disco di sola lettura, di 8 pollici (20 cm) di diametro, chiamato “memory disk”. La prima commercializzazione è avvenuta nel 1971.