Punched Card

The origins of the use of punched cards for data processing and storage can be traced back to the German-American inventor Herman Hollerith, who sped up and partially mechanised the processing of data during the 1890 US census (an official survey of the population) by using punched cards to record each person's information. Data is stored on the card by punching holes, which represent letters or numbers, in specific column locations that relate to the information being recorded. To read this data, the card must be run through a machine that can detect or ‘sense’ the location of the holes.

The original Hollerith code format was based on a rectangular paper punched card with 45 columns and round punched holes. However, the standard and more widely used format (shown in this image), introduced by International Business Machines Co. Ltd. (IBM) in 1928, had 80 columns, 12 rows and rectangular punched holes; it was specifically designed to be the same size as an 1890 American dollar bill.