Herman Hollerith's Punched Card Tabulating Machine Automates the 1890 U.S. Census

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Herman Hollerith's Punched Card Tabulating Machine Automates the 1890 U.S. Census

Overview

By successfully automating the calculation of the 1890 United States census with an electro-mechanical punch-card device, inventor Herman Hollerith (1860-1929) laid the foundation for the next century's explosion of information-processing machines, technologies, systems, and businesses, including IBM, the world's largest computer corporation. Hollerith's use of standardized punched cards to represent information, and his addition of electricity to mechanical tabulation, greatly increased the effectiveness and range of applications of tabulating and, later, computing machines.

Background

The explosive growth of industry and population throughout the nineteenth century was matched and in some ways exceeded by growth in the amount of information those industries and people generated. There was an important and expanding need to manage and manipulate the statistics derived from that information, both for social/political and economic purposes. For example, while the 1850 census allowed for 60 different statistical entries regarding race and sex, there were more than 1,600 such entries in the 1890 census. The world was in danger of drowning in data. There was an increasing demand not only for more accurate recordskeeping but also for faster calculations and tabulations of those records.

For the most part the statistics were recorded and tabulated by hand, although mechanical calculating devices that used gears and levers to record numbers had been employed with varying degrees of success throughout the century. (Indeed, simple aids to calculation had been used for thousands of years; the abacus, with its movable beads, is a good example of such a device, and has been in existence for more than 5,000 years.) Mechanical calculating devices were primarily useful for simple addition, and still required a great deal of human labor, including the painstaking recording and transcription of data before and after the calculating process itself. Still, it was clear that mechanical assistants could make simpler all manner of arithmetical operations.

Early in the nineteenth century, English inventor Charles Babbage (1792-1871) built the first of several mechanical calculating machines, which he called difference engines. Completed in 1822, Babbage's first difference engine was intended to handle a variety of calculating and computing tasks, and to print the results of its computations either on paper or on printer's plates. Babbage continued to refine and enhance his engines until his death in 1871. While Babbage's machines were marvels of design and operation, they remained difficult to operate, and less precise than desired.

Still, the importance of mechanical aids for computation could not be denied, and by the 1880s, research into computing machines was proceeding at a rapid pace. Various approaches were taken to increase the effectiveness of mechanical calculators, none more successful than the innovations introduced by American inventor Herman Hollerith. It occurred to Hollerith—as it had to others—that since statistics are patterns of information, they could perhaps be encoded in ways similar to those used in mechanical looms to weave patterns of thread into fabric. That process, using cards with holes punched in them to guide the loom's workings, had been developed in France more than a hundred years before by Joseph Marie Jacquard (1752-1834). The Jacquard loom had revolutionized the textile industry; now Hollerith sought to adapt the technology to weaving patterns of statistics.

By May 1883, now working for the United Sates Patent Office in Washington, Hollerith had roughed out his idea. Central to the idea—and one of the keys to Hollerith's great contribution—was the use of electricity to automate the recording of information.

Holes punched in strips of paper would represent different types of information. The paper would be fed into a mechanical device comprised of a hand press which pushed metal pins into contact with the paper strip. Those pins which passed through punched holes would make contact with a container of mercury, completing an electric circuit; where no hole was encountered, no contact would be made. Completed circuits in turn triggered mechanical counters which recorded the appropriate information. There had been mechanical calculators before Hollerith, but his introduction of electricity into the equipment dramatically increased their efficiency—and potential.

Another of his innovations was the replacement of strips of paper with punched cards. These stiff cards proved far easier to sort and manipulate than paper, further enhancing the speed of calculating operations. Over the next three decades Hollerith and his company would work to standardize the size and format of punched cards. Standardization was vital to the spread of tabulating—and, later, true computing—as an industry.

Hollerith machines were used to calculate the 1890 United States census. His Tabulating Machine Company accomplished the calculation of population in less than six months, and the rest of the census information in under two years, far more rapidly than any census had ever been completed. Also attracting attention was the fact that Hollerith's machines performed their tasks far more economically than could human calculators. The census was completed more than $5 million below its budget.

Impact

The impact of Hollerith's innovation was both immediate and long-lasting. The immediate impact was simply an increased demand for his machines by governments and industries throughout the world. In 1897, for example, Hollerith systems were used to calculate the Russian census. For that task, more than 100 million punched cards were employed.

While census calculation formed the heart of Hollerith's business throughout the 1890s, other applications and uses for electromechanical computation were clear. Virtually any undertaking that relied on numbers or statistics could automate its calculations, saving money and increasing efficiency. Hollerith's tabulating systems found ready use in the calculation of railroad freight shipments, agricultural output, insurance and banking figures, and so on.

Many of these applications required features unavailable in the first Hollerith machines, including multiplication and division. Hollerith continued to innovate, adding these and other mathematical features, as well as introducing printed output of results. With the widespread arrival of electrical power Hollerith added that as well, producing true electrical calculators rather than electrochemical ones. He and his engineers continued to automate various aspects of their equipment, notably the punching of holes in cards, and the sorting of those cards.

The uses of Hollerith tabulators—and machines from competing companies—continued to spread. United States President Theodore Roosevelt foresaw ways in which social reform and government policies could be shaped and directed as a result of statistics generated by the census, as well as other information sources. In addition to industry and government, the sciences also found many uses for mechanical calculators.

The business of calculation grew as well. Hollerith perceived not only the need for large-scale calculating and computing services, but also the all-but-unlimited potential demand for such services as data entry, machine maintenance and servicing, equipment upgrades, and so on. One of his business innovations, which influenced the computer industry for most of the century, was his policy of leasing, rather than selling his tabulating machines. Leases tended to be more affordable than outright purchase, and had the added advantage of insuring Hollerith a continuing market for services and cards.

In 1911 Hollerith's Tabulating Machine Company merged with the International Time Recording Company and two other companies to form the Computing-Tabulating-Recording Company (CTR) with Hollerith as president. He continued to work with the firm for another decade, retiring in 1921. He died eight years later.

CTR changed its name in 1924, becoming International Business Machines (IBM.) As the world's largest supplier of calculating and tabulating machines, as well as the punched cards on which information was recorded, this offspring of Hollerith's original firm shaped the role of information management for governments, businesses, and institutions throughout the twentieth century.

As other technologies emerged, IBM—and its competitors—incorporated them into their products. The arrival of electronics, first in the form of vacuum tubes, later in the form of transistors and printed circuits, hastened the transformation of calculating machines into true computers, able to accomplish billions of calculations of all types in seconds. While still primarily statistical machines, computers played increasingly important roles throughout society. The twentieth century, in fact, came to be referred to as the Information Age, a fact largely made possible by our ability, thanks to calculating, tabulating, and computing machines, to process and manage information.

With the expansion of the computer's abilities during the second half of the twentieth century, as well as their decreasing size and cost, computers became perhaps the world's single-most-important technology. Complex modern society and business would be all but unmanageable without these descendants of early tabulating machines. Everything from systems of traffic lights to telephone networks to inventories at stores and factories came to be automated by computers. The arrival, late in the 1970s, of small, relatively inexpensive personal computers extended the usefulness of computers to individuals.

The marriage of computers with telecommunications created, by the last decade of the century, a global network of information, commerce, communication, entertainment, and education unlike anything the world had seen—all barely a century after Hollerith used punched paper to calculate the United States census.

KEITH FERRELL