Hollerith, IBM, and Punched Card Data Processing

Key Insight

The practical demands of large-scale data processing, particularly the U.S. decennial census mandated by the Constitution, spurred the next major advancement in computing. The 1880 census data took approximately seven years to process, raising concerns that the 1890 census would exceed a decade. Herman Hollerith (1860–1929), a statistician for the 1880 census, developed machinery to automate this task. His system utilized manila punch cards, measuring 6 5/8 by 3 1/4 inches, which were organized into 24 columns of 12 positions each, totaling 288 potential punch positions to represent specific personal characteristics.

Hollerith's cards were not designed for a purely binary system, instead employing a more human-friendly, practical coding. For example, sex was indicated by punching one of two specific positions (male or female), and age required two punches across 28 positions, compared to just 7 positions for a binary system. This approach simplified data entry for census takers and made the cards structurally sounder, avoiding fragility from numerous holes. To process these cards, Hollerith created a tabulating machine that combined hand operation with automation. An operator pressed a board of 288 spring-loaded pins onto each card; pins corresponding to punched holes contacted a pool of mercury, completing an electrical circuit to trigger an electromagnet and increment a decimal counter.

Hollerith also developed a sorting machine, which used the same hand press as the tabulator but employed electromagnets to open a hatch to one of 26 separate compartments, allowing cards to be sorted. The automation of the 1890 census was a resounding success, processing over 62 million cards, which contained twice the data of the 1880 census, in about one-third the time. Hollerith and his inventions gained international recognition, notably used in the first Russian census in 1897. In 1896, Hollerith founded the Tabulating Machine Company, which, through mergers, became the Computing-Tabulating-Recording Company (C-T-R) by 1911. Thomas J. Watson, C-T-R's president in 1915, renamed it International Business Machines Corporation (IBM) in 1924. By 1928, the original census cards had evolved into the iconic 80-column, 12-row IBM cards, which remained in active use for over 50 years.