In 1959, IBM released the IBM 1620 data processing system.
The IBM 1620 was a small, transistorized inexpensive scientific computer that could perform more than 100,000 calculations a minute. In the eleven years that it was on the market, approximately two thousand units were sold.
Learn more at http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP1620.html.