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The tabulating machine was an electromechanical machine designed to assist in summarizing information and, later, accounting. Invented by Herman Hollerith, the machine was developed to help process data for the 1890 U.S. Census. 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 1920 date on page 95 is incorrect, see (The Columbia Difference Tabulator - 1931 )〕 ==1890 census== The 1880 census had taken seven years to process, and by the time the results were available, they were clearly obsolete.〔U.S. Census, 1880#Results〕 Due to rapid growth of the U.S. population from 1880 to 1890, primarily because of immigration, it was estimated that the 1890 census would take approximately 13 years to complete — an immense logistical problem. Since the U.S. Constitution mandates a census every ten years to apportion representatives and direct taxes between the states, a faster method was necessary. 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 and mechanized musical instruments. "After some initial trials with paper tape, he settled on punched cards..."〔(Columbia University Computing History - Herman Hollerith )〕 Hollerith used punched cards with round holes, 12 rows and 24 columns. His tabulator used electromechanical relays (and 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 〔(Holerith 1890 Census Tabulator ) Columbia University Computing History〕 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. This arrangement allowed a count up to 10,000. During a given tabulating run, counters could be assigned a specific hole or, using relay logic, a combination of holes, e.g. to count married females. Hollerith's method was used for the 1890 census. The cards were coded for age, state of residence, gender, and other information. Clerks used keypunches to punch holes in the cards to enter information from the returns. The census results were "... finished months ahead of schedule and far under budget."〔(U.S. Census Bureau: Tabulation and Processing )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tabulating machine」の詳細全文を読む スポンサード リンク
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