Disk performance gains
  IBM 350 RAMAC
(1955)
IBM 3330
(1970)
IBM 3380
(1980)
IBM 3390
(1989)
Information Per Volume 5 million characters 100 million characters 630 million characters 1890 million characters
Time needed to Access Disks 600/1,000ths of a second 30/1,000ths of a second 16/1,000ths of a second 12.5/1,000ths of a second
Read-Write Speed 9,700 characters a second 806,000 characters a second 3 million characters a second 4.2 million characters a second

Note: A volume measurement is used here for consistency. A volume is the portion of a single unit disk storage accessible to a single read/write mechanism, for example, a head disk assembly, disk pack, actuator or a drum.