Hollerith, Herman

Hollerith, Herman

(1860–1929) American

Inventor

Herman Hollerith invented the automatic tabulating machine, a device that could read the data on punched cards and dis-play running totals. His invention would become the basis for the data tabulating and processing industry. Hollerith was born in Buffalo, New York, and graduated from the Columbia School of Mines. After graduation, he went to work for the U.S. Census as a statistician. Among other tasks he compiled vital statistics for Dr. John Shaw Billings, who suggested to Hollerith that using punched cards and some sort of tabulator would help the Census Department keep up with the growing volume of demographic statistics.

Hollerith studied the problem and decided that he could build a suitable machine. He went to MIT, where he taught mechanical engineering while working on the machine, which was partly inspired by an earlier device that had used a piano-type roll rather than punched cards as input. The peripatetic Hollerith soon got a job with the U.S. Patent Office, partly to learn the procedures he would need to fol-low to patent his tabulator. He applied for several patents, including one for the punched-card tabulator. He tested the device with vital statistics in Baltimore, New York, and the state of New Jersey.

Hollerith’s mature system included a punch device that a clerk could use to record variable data in many categories on the same card (a stack of cards could also be prepunched with constant data, such as the number of the census dis-trict). The cards were then fed into a device something like a small printing press. The top part of the press had an array of spring-loaded pins that connected to tiny pots of mercury (an electrical conductor) in the bottom. The pins were electrified. Where a pin encountered a punched hole in the card, it penetrated through to the mercury, allowing current to flow. The current created a magnetic field that moved the corresponding counter dial forward one posi-tion. The dials could be read after a batch of cards was fin-ished, giving totals for each category, such as an ethnicity or occupation. The dials could also be connected to count multiple conditions (for example, the total number of for-eign-born citizens who worked in the clothing trade).

Aided by Hollerith’s machines, a census unit was able to process 7,000 records a day for the 1890 census, about ten times the rate in the 1880 count. Starting around 1900, Hollerith brought out improved models of his machines that included such features as an automatic (rather than hand-fed) card input mechanism, automatic sorters, and tabulators that boasted a much higher speed and capacity. Hollerith machines soon found their way into government agencies involved with vital statistics, agricultural statis-tics, and other data-intensive matters, as well as insurance companies and other businesses.

Facing vigorous competition and in declining health, Hollerith sold his patent rights to the company that even-tually evolved into IBM, the company that would come to dominate the market for tabulators, calculators, and other office machines. The punched card, often called the Hollerith card, would become a natural choice for com-puter designers and would remain the principal means of data and program input for mainframe computers until the 1970s.