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Portrait of Herman Hollerith
The early style round hole census punch card
Herman Hollerith - Image from www.historia.et.tudelft.nl/wggesch/ geschiedenis/computer/
The original punch card design - Image from www.tcf.ua.edu/AZ/ ITHistoryOutline.htm

Herman Hollerith - Inventor of the "punch card"

Born 1860 - Died 1929 - Invention Attributed to the year 1887

Information provided below by Gregory M. Walters, based on data collected from online sources as listed. gwalters@pstcc.edu

Herman Hollerith worked for the US Census as a statistician and in 1880 he observed first hand how much data had to be analyzed by hand and counted using pencil and paper processes. That census took eight years to complete. Mr. Hollerith realized that a mechanical means needed to be found to help with this awesome task that took years to produce. For a time he had taught classes at the Massachusetts Institute of Technology in the field of mechanical engineering and had marveled at Jacquard's automated weaving looms. He made the connection between his work and the punch cards being used to duplicate designs on the looms as he rode on a train one day. He watched a ticket collector punch tickets and found out that each hole had a specific purpose identifying the holder. After some experimentation he was able to create a hole punch coding system that could represent any letter in the alphabet or any grouping of digits to form a number. This was a revolutionary new concept as it was probably the first real use of data storage and data use by a machine to do calculating. He invented and patented a machine to make the holes and more importantly another machine shown above that was used to read and calculate the data from the card. What took hours could now be done in minutes as mechanical pins simultaneously passed through the holes in the cards to make electrical contact and advancing counter dials. An automated electrical counting and storage machine was born; the Hollerith Tabulating Machine. After extensive testing and refinement the machine was placed into service for the 1890 census. Instead of taking years to calculate, the census was done in about three months. It was probably far more accurate than any previous census too. Data gathering was more complete also with new data being collected for the first time. It saved the United States 5 million dollars for the 1890 census by completing the analysis of the data in a fraction of the time it would have taken without it and with a smaller amount of manpower than would have been necessary otherwise. The system was again used for the 1891 census in Canada and later in other countries. The Hollerith system was considered a great leap forward in technology and the punch card continued to be used until the early 1980's as one of the major data entry and storage components on any and all computer systems. In 1896 Hollerith founded the Tabulating Machine Company. He greatly improved the machine and the new model was used in 1900 complete with automatic feed mechanisms to automate the procedure even more. Later Hollerith merged with a rival and in 1924 the company was renamed to International Business Machines (IBM). Modern versions of the keypunch would have a regular keyboard, but the earliest versions looked like this. The last design of the 80 column punch card (each column holds one character) and the final design using a 96 column card are shown in these two links.

Sites used as sources for this page:







also note sites listed as image captions above

Note: It is unknown if Herman Hollerith ever knew of the Charles Babbage designs. It is not mentioned in any of his writings. It could be that the train story was a fabrication to insure his "original punch card data storage" idea was allowed to be patented. Babbage did have notes using such ideas, but of course his invention was never completed. We will never know if Hollerith stole this idea or not.

FYI: The punch card code that went into computers in later years was called EBCDIC (Extended Binary Coded Decimal Interchance Code).

Page generated March 14, 2003

Last revision/update April 25, 2003


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