Punched Cards

History of Computing – Punch card computing

The U.S. census department must perform a census every 10 years. In 1880 the actual head count required only a few months, but tabulating and analyzing the data took nine years to complete. Recognizing a problem in need of a solution, Herman Hollerith developed a system that used punched cards and special machines that could tabulate the data recorded on the cards. The system was quite simple. Data about a person, such as age, sex, and marital status, were recorded on a card by punching holes in the proper positions. The data on the card were counted by a machine operated by a human. The card was placed in a reader station. The operator applied a press containing pins that corresponded to each possible position where a hole could be punched. In locations where a hole was punched, a pin would make contact with a connection on the other side of the card and a counter would be incremented.

Through various trials and tests, Hollerith’s system proved to be a vast improvement over previous tabulation methods. Hollerith formed a company, called the Tabulating Machine Company, and rented machines to the census department to perform the 1890 census. The tally of the total number of people in the United States was available six weeks after the head count began, and the final statistics were available in seven years. A two-year reduction may not seem like much of an improvement, but the 1890 census included a far more thorough and detailed analysis of the raw data.

Hollerith’s system was featured on the cover of the August 1890 issue of Scientific American, and it was adopted by countries all over Europe. Eventually, companies began using the system to do accounting and inventory. Hollerith’s company experienced phenomenal growth and eventually merged with several others; it ultimately became one of the giants in the computing industry, International Business Machines (IBM).

Culled from C++ Program Design – An Introduction to Programming and Object-Oriented Design by James P. Cohoon/Jack W. Davidson (2nd Edition)





9 responses to “History of Computing – Punch card computing”

  1. Ugochukwu Avatar

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    1. caseraycloud Avatar

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  2. Ugoboy Avatar

    Very inspiring

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