written ST506 and ST412) were early harddiskdrive products introduced by Seagate in 1980 and 1981 respectively, that later became construed as harddisk drive
5.25-inch (Segate ST225) drive with ST506 interface (became later the Megafile 20) Megafile 20, 30, 60: External harddrive, Mega ST matching case, ACSI
bytes) harddiskdrive was introduced in 2007. Decimal prefixes were generally used by information processing publications when comparing harddisk capacities