The IBM 1311 Disk Storage Drive
provided storage for two million characters. Debuting
in 1962, the 1311 used the IBM Disk Pack -- an interchangeable
package containing six 14-inch-diameter disks in
a four-inch stack, weighing 10 pounds. Some analysts
believe that the removable disk pack not only led
to a new phase of disk storage but signaled the
passing of the punched card era.