 Disk media diameter was initially 24 inches in diameter, but over time it has been reduced to today's 3.5-inch and 2.5-inch standard sizes.Drives with the larger 24-inch- and 14-inch-diameter media were typically mounted in standalone boxes (resembling washing machines) or large equipment rack enclosures.Individual drives often required high-current AC power due to the large motors required to spin the large disks.