Tabulating machine

The tabulating machine was an electromechanical machine designed to assist in summarizing information stored on punched cards. Invented by Herman Hollerith, the machine was developed to help process data for the 1890 U.S. Census. Later models were widely used for business applications such as accounting and inventory control. It spawned a class of machines, known as unit record equipment, and the data processing industry. The term "Super Computing" was used by the New York World newspaper in 1931 to refer to a large custom-built tabulator that IBM made for Columbia University. The 1880 census had taken two years to process. Since the U.S. Constitution mandates a census every ten years to apportion both congressional representatives and direct taxes among the states, a combination of larger staff and faster-recording systems was required. In the late 1880s Herman Hollerith, inspired by conductors using holes punched in different positions on a railway ticket to record traveler details such as gender and approximate age, invented the recording of data on a machine-readable medium. Prior uses of machine-readable media had been for lists of instructions (not data) to drive programmed machines such as Jacquard looms. "After some initial trials with paper tape, he settled on punched cards..." Hollerith used punched cards with round holes, 12 rows, and 24 columns. The cards measured inches by 6-5/8 inches. His tabulator used electromechanical solenoids to increment mechanical counters. A set of spring-loaded wires were suspended over the card reader. The card sat over pools of mercury, pools corresponding to the possible hole positions in the card. When the wires were pressed onto the card, punched holes allowed wires to dip into the mercury pools, making an electrical contact that could be used for counting, sorting, and setting off a bell to let the operator know the card had been read. The tabulator had 40 counters, each with a dial divided into 100 divisions, with two indicator hands; one which stepped one unit with each counting pulse, the other which advanced one unit every time the other dial made a complete revolution.