page_title: Unit record equipment
section_title: Tabulating
hierarchical_section_title: Unit record equipment / Tabulating
context_page_description: Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using electromechanical machines called unit record equipment, electric accounting machines or tabulating machines.
  Unit record machines came to be as ubiquitous in industry and government in the first two-thirds of the twentieth century as computers became in the last third. They allowed large volume, sophisticated data-processing tasks to be accomplished before electronic computers were invented and while they were still in their infancy. This data processing was accomplished by processing punched cards through various unit record machines in a carefully choreographed progression. This progression, or flow, from machine to machine was often planned and documented with detailed flowcharts that used standardized symbols for documents and the various machine functions. All but the earliest machines had high-speed mechanical feeders to process cards at rates from around 100 to 2,000 per minute, sensing punched holes with mechanical, electrical, or, later, optical sensors.
context_section_description: Reports and summary data were generated by accounting or tabulating machines. The original tabulators only counted the presence of a hole at a location on a card. Simple logic, like ands and ors could be done using relays.
  Later tabulators, such as those in IBM's 300 series, directed by a control panel, could do both addition and subtraction of selected fields to one or more counters and print each card on its own line. At some signal, say a following card with a different customer number, totals could be printed for the just completed customer number.  Tabulators became complex: the IBM 405 contained 55,000 parts (2,400 different) and 75 miles of wire; a Remington Rand machine circa 1941 contained 40,000 parts.
caption: An IBM 407 Accounting Machine at US Army's Redstone Arsenal in 1961.
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