1956
IBM brings out the Magnetic Disk Memory

IBM brings out the "Magnetic Disk Memory" : RAMAC350 - Random Access Method of Accounting and Control.

The era of magnetic disk storage dawned with IBM's shipment of a 350 RAMAC to Zellerbach Paper in San Francisco. The IBM 350 disk served as the storage component for the RAMAC.  This "machine" is man's height, contains 50 steel platters coated with a magnetic layer. The platters are mounted on a vertical shaft that drives them around. The read and write heads do not move. The total capacity of the system is 5 million bytes ("characters").