Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using electromechanical machines collectively referred to as unit record equipment, electric accounting machines (EAM) or tabulating machines.[1][2][3][4] 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.[5] 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.[6] 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. The operation of many machines was directed by the use of a removable plugboard, control panel, or connection box.[7] Initially all machines were manual or electromechanical. The first use of an electronic component was in 1937 when a photocell was used in a Social Security bill-feed machine.[8]: 65  Electronic components were used on other machines beginning in the late 1940s.

The term unit record equipment also refers to peripheral equipment attached to computers that reads or writes unit records, e.g., card readers, card punches, printers, MICR readers.

IBM was the largest supplier of unit record equipment and this article largely reflects IBM practice and terminology.

Sheet 1 of Hollerith's U.S. Patent 395,782 showing his early concept for recording statistical information by means of holes punched in paper.
Sheet 1 of Hollerith's U.S. Patent 395,782 showing his early concept for recording statistical information by means of holes punched in paper.



In the 1880s Herman Hollerith invented the recording of data on a medium that could then be read by a machine.[dubious ] 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 [...]".[9] To process these punched cards, sometimes referred to as "Hollerith cards", he invented the keypunch, sorter, and tabulator unit record machines.[10][11] These inventions were the foundation of the data processing industry. The tabulator used electromechanical relays to increment mechanical counters. Hollerith's method was used in the 1890 census. The company he founded in 1896, the Tabulating Machine Company (TMC), was one of four companies that in 1911 were amalgamated in the forming of a fifth company, the Computing-Tabulating-Recording Company, later renamed IBM.

Following the 1900 census a permanent Census bureau was formed. The bureau's contract disputes with Hollerith led to the formation of the Census Machine Shop where James Powers and others developed new machines for part of the 1910 census processing.[12] Powers left the Census Bureau in 1911, with rights to patents for the machines he developed, and formed the Powers Accounting Machine Company.[13] In 1927 Powers' company was acquired by Remington Rand.[14] In 1919 Fredrik Rosing Bull, after examining Hollerith's machines, began developing unit record machines for his employer. Bull's patents were sold in 1931, constituting the basis for Groupe Bull.

These companies, and others, manufactured and marketed a variety of general-purpose unit record machines for creating, sorting, and tabulating punched cards, even after the development of computers in the 1950s. Punched card technology had quickly developed into a powerful tool for business data-processing.


Replica of Hollerith tabulating machine with sorting box, circa 1890. The "sorting box" was an adjunct to, and controlled by, the tabulator.  The "sorter", an independent machine, was a later development.[15]
Replica of Hollerith tabulating machine with sorting box, circa 1890. The "sorting box" was an adjunct to, and controlled by, the tabulator. The "sorter", an independent machine, was a later development.[15]
Hollerith machine in use at the London School of Economics in 1964
Hollerith machine in use at the London School of Economics in 1964

By the 1950s punched cards and unit record machines had become ubiquitous in academia, industry and government. The warning often printed on cards that were to be individually handled, "Do not fold, spindle or mutilate", coined by Charles A. Philips, became a motto for the post-World War II era (even though many people had no idea what spindle meant).[57]

With the development of computers punched cards found new uses as their principal input media. Punched cards were used not only for data, but for a new application - computer programs, see: Computer programming in the punched card era. Unit record machines therefore remained in computer installations in a supporting role for keypunching, reproducing card decks, and printing.

Many organizations were loath to alter systems that were working, so production unit record installations remained in operation long after computers offered faster and more cost effective solutions. Specialized uses of punched cards, including toll collection, microform aperture cards, and punched card voting, kept unit record equipment in use into the twenty-first century. Another reason was cost or availability of equipment: for example in 1965 an IBM 1620 computer did not have a printer as standard equipment, so it was normal in such installations to punch printed output onto cards, using two cards per line if required and print these cards on an IBM 407 accounting machine and then throw the cards away.


Punched cards

Main article: Punched card

The basic unit of data storage was the punched card. The IBM 80-column card was introduced in 1928. The Remington Rand Card with 45 columns in each of two tiers, thus 90 columns, in 1930.[76] Powers-Samas punched cards include one with 130 columns.[77] Columns on different punch cards vary from 5 to 12 punch positions.

The method used to store data on punched cards is vendor specific. In general each column represents a single digit, letter or special character. Sequential card columns allocated for a specific use, such as names, addresses, multi-digit numbers, etc., are known as a field. An employee number might occupy 5 columns; hourly pay rate, 3 columns; hours worked in a given week, 2 columns; department number 3 columns; project charge code 6 columns and so on.


Main article: Keypunch

IBM 029 Card Punch.
IBM 029 Card Punch.

Original data were usually punched into cards by workers, often women, known as keypunch operators, under the control of a program card (called a drum card because it was installed on a rotating drum in the machine), which could automatically skip or duplicate predefined card columns, enforce numeric-only entry, and, later, right-justify a number entered.

Their work was often checked by a second operator using a verifier machine, also under the control of a drum card. The verifier operator re-keyed the source data and the machine compared what was keyed to what had been punched on the original card.


Main article: Punched card sorter

See also: IBM 80 series Card Sorters and IBM 101 Electronic Statistical Sorting Machine

IBM 082 Sorter.
IBM 082 Sorter.

An activity in many unit record shops was sorting card decks into the order necessary for the next processing step. Sorters, like the IBM 80 series Card Sorters, sorted input cards into one of 13 pockets depending on the holes punched in a selected column and the sorter's settings. The 13th pocket was for blanks and rejects. Cards were sorted on one card column at a time; sorting on, for example, a five digit zip code required that the card deck be processed five times. Sorting an input card deck into ascending sequence on a multiple column field, such as an employee number, was done by a radix sort, bucket sort, or a combination of the two methods.

Sorters were also used to separate decks of interspersed master and detail cards, either by a significant hole punch or by the cards corner-cut.[78]

More advanced functionality was available in the IBM 101 Electronic Statistical Machine, which could


Main article: Tabulating machine

An IBM 407 Accounting Machine at US Army's Redstone Arsenal in 1961.
An IBM 407 Accounting Machine at US Army's Redstone Arsenal in 1961.

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.[23][80]


In 1931, IBM introduced the model 600 multiplying punch. The ability to divide became commercially available after World War II. The earliest of these calculating punches were electromechanical. Later models employed vacuum tube logic. Electronic modules developed for these units were used in early computers, such as the IBM 650. The Bull Gamma 3 calculator could be attached to tabulating machines, unlike the stand-alone IBM calculators.[54]

Further information: IBM 602 Calculating Punch; IBM 603 Electronic Multiplier; IBM 604 Electronic Calculating Punch; IBM 608 Calculator; IBM Card-Programmed Electronic Calculator (IBM CPC); and Remington Rand 409 (aka. UNIVAC 60, 120)

Card punching

IBM 519 Document-Originating Machine
IBM 519 Document-Originating Machine

Card punching operations included:

Singularly or in combination, these operations were provided in a variety of machines. The IBM 519 Document-Originating Machine could perform all of the above operations.

The IBM 549 Ticket Converter read data from Kimball tags, copying that data to punched cards.

Further information: IBM 513 Reproducing Punch, IBM 514 Reproducing Punch, and IBM 519 Document-Originating Machine

With the development of computers, punched cards were also produced by computer output devices.


IBM collators had two input hoppers and four output pockets. These machines could merge or match card decks based on the control panel's wiring as illustrated here.

The Remington Rand Interfiling Reproducing Punch Type 310-1 was designed to merge two separate files into a single file. It could also punch additional information into those cards and select desired cards.[76]

Collators performed operations comparable to a database join.


See also: IBM 550 Numerical Interpreter and IBM 557 Alphabetic Interpreter

Punched card bill with selected columns interpreted at the top
Punched card bill with selected columns interpreted at the top

An interpreter prints characters on a punched card equivalent to the values of all or selected columns. The columns to be printed can be selected and even reordered, based on the machine's control panel wiring. Later models could print on one of several rows on the card. Unlike keypunches, which print values directly above each column, interpreters generally use a font that was a little wider than a column and can only print up to 60 characters per row.[82] Typical models include the IBM 550 Numeric Interpreter, the IBM 557 Alphabetic Interpreter, and the Remington Rand Type 312 Alphabetic Interpreter.[76]


Batches of punched cards were often stored in tub files, where individual cards could be pulled to meet the requirements of a particular application.

Transmission of punched card data

See also: IBM 1013 Card Transmission Terminal

Electrical transmission of punched card data was invented in the early 1930s. The device was called an Electrical Remote Control of Office Machines and was assigned to IBM. Inventors were Joseph C. Bolt of Boston & Curt I. Johnson; Worcester, Mass. assors to the Tabulating Machine Co., Endicott, NY. The Distance Control Device received a US patent in Aug.9,1932: U.S. Patent 1,870,230. Letters from IBM talk about filling in Canada in 9/15/1931.

Processing punched tape

The IBM 046 Tape-to-Card Punch and the IBM 047 Tape-to-Card Printing Punch (which was almost identical, but with the addition of a printing mechanism) read data from punched paper tape and punched that data into cards. The IBM 063 Card-Controlled Tape Punch read punched cards, punching that data into paper tape.[83]

Control panel wiring and Connection boxes

IBM 402 Accounting Machine control panel[84]
IBM 402 Accounting Machine control panel[84]

Main article: Wiring of unit record equipment

The operation of Hollerith/BTM/IBM/Bull tabulators and many other types of unit record equipment was directed by a control panel.[85] Operation of Powers-Samas/Remington Rand unit record equipment was directed by a connection box.[86]

Control panels had a rectangular array of holes called hubs which were organized into groups. Wires with metal ferrules at each end were placed in the hubs to make connections. The output from some card column positions might connected to a tabulating machine's counter, for example. A shop would typically have separate control panels for each task a machine was used for.

Paper handling equipment

Main article: Continuous stationery

A decollator and a burster
A decollator and a burster

For many applications, the volume of fan-fold paper produced by tabulators required other machines, not considered to be unit record machines, to ease paper handling.

See also

Notes and references

  1. ^ Origin of the term unit record: It was in 1888 that Mr. Davidson conceived the idea... The idea was that the card catalog, then in fairly general use by libraries, could be adapted with advantage to certain 'commercial indexes'. ... Directly connected with these is one of the most important principles of all - the 'unit record' principal in business. Hitherto, the records of a business house had been kept, each for one fixed purpose, and their usefulness had been restricted by the inflexible limitations of a bound book. The unit record principle, made possible by the card system, gave to these records a new accessibility and significance. ... The Story of the Library Bureau. Cowen Company, Boston. 1909. p. 50.
  2. ^ By 1887 ...Doctor Herman Hollerith had worked out the basis for a mechanical system of recording, compiling and tabulating census facts... Each card was used to record the facts about an individual or a family - a unit situation. These cards were the forerunners of today's punched cards or unit records. General Information Manual: An Introduction to IBM Punched Card Data Processing. IBM. p. 1.
  3. ^ Data processing equipment can be divided into two basic types - computers and unit record machines. Unit Record derives form the common use of punchcards to carry information on a one-item-per-card basis, which makes them unit records. Janda, Kenneth (1965). Data Processing. Northwestern University Press. p. 47.
  4. ^ Like the index card, the punched card is a unit record containing one kind of data, which can be combined with other kinds of data punched in other cards. McGill, Donald A.C. (1962). Punched Cards, Data Processing for Profit Improvement. McGraw-Hill. p. 29.
  5. ^ International Business Machines Corp. (1957). Machine Functions (PDF). 224-8208-3. ((cite book)): |author= has generic name (help)
  6. ^ International Business Machines Corp. (1959). Flow Charting and Block Diagramming Techniques (PDF). /C20-8008-0. ((cite book)): |author= has generic name (help)
  7. ^ Cemach, Harry P., 1951, The Elements of Punched Card Accounting, Pitman, p.27. Within certain limits the information punched in any column of a card can be reproduced in any desired position by the tabulator. This is achieved by means of a Connection Box. ... The connection box can be easily removed from the tabulator and replaced by another.
  8. ^ a b c d e f g Pugh, Emerson W. (March 16, 1995). Building IBM: Shaping an Industry and Its Technology. MIT Press. ISBN 978-0262161473.
  9. ^ Columbia University Computing History - Herman Hollerith
  10. ^ U.S. Census Bureau: The Hollerith Machine
  11. ^ An early use of "Hollerith Card" can be found in the 1914 Actuarial Soc of America Trans. v.XV.51,52- Perforated Card System
  12. ^ Truesdell, Leon E. (1965). The Development of Punch Card Tabulation in the Bureau of the Census 1890-1940. US GPO.
  13. ^ U.S. Census Bureau: Tabulation and Processing
  14. ^ a b A History of Sperry Rand Corporation (4th ed.). Sperry Rand. 1967. p. 32.
  15. ^ a b Austrian, Geoffrey D. (1982). Herman Hollerith: Forgotten Giant of Information Processing. Columbia University Press. pp. 41, 178–179. ISBN 0-231-05146-8.
  16. ^ a b Truesdell, Leon Edgar (1965). The development of punch card tabulation in the Bureau of the Census, 1890-1940: with outlines of actual tabulation programs. U.S. G.P.O. pp. 84–86.
  17. ^ "IBM Archives: Hollerith Automatic Horizontal Sorter". 23 January 2003.
  18. ^ Austrian, 1982, p.216
  19. ^ Computing at Columbia: Timeline - Early
  20. ^ Durand, Hon. E. Dana (September 23–28, 1912). Tabulation by Mechanical Means - Their Advantages and Limitations, volume VI. Transactions of the Fifteenth International Congress on Hygiene and Demography.
  21. ^ Cortada, James W. (February 8, 1993). Before the Computer: IBM, NCR, Burroughs, & Remington Rand & The Industry they Created 1865—1956. Princeton University Press. pp. 56–59. ISBN 978-0691048079.
  22. ^ Cemach, Harry P. (1951). The Elements of Punched Card Accounting. Pitman. p. 5.
  23. ^ a b c Know-How Makes Them Great. Remington Rand. 1941.
  24. ^ a b IBM Archives: Endicott chronology, 1951-1959
  25. ^ a b c d e f g h Information Technology Industry TimeLine
  26. ^ a b Cortada p.57
  27. ^ a b Van Ness, Robert G. (1962). Principles of Punched Card Data Processing. The Business Press. p. 15.
  28. ^ Punched Hole Accounting. IBM. 1924. p. 18.
  29. ^ Engelbourg p.173
  30. ^ "IBM Archives: 1920". IBM. 23 January 2003.
  31. ^ Rojas, Raul, ed. (2001). Encyclopedia of Computers and Computer History. Fitzroy Dearborn. p. 656.
  32. ^ Aspray, William, ed. (1990). Computing Before Computers. Iowa State University Press. p. 137. ISBN 0-8138-0047-1.
  33. ^ IBM Type 80 Electric Punched Card Sorting Machine
  34. ^ IBM 301 Accounting Machine (the Type IV)
  35. ^ Columbia University Professor Ben Wood
  36. ^ The Origins of Cybersace. Christie's. 2005. p. 14.
  37. ^ Heide, Lars (2002) National Capital in the Emergence of a Challenger to IBM in France Archived March 4, 2016, at the Wayback Machine
  38. ^ H.W.Egli - BULL Tabulator model T30 Archived May 7, 2012, at the Wayback Machine
  39. ^ a b c d e f Bashe, Charles J.; Johnson, Lyle R.; Palmer, John H.; Pugh, Emerson W. (1986). IBM's Early Computers. MIT Press. ISBN 0-262-02225-7.
  40. ^ Eames, Charles; Eames, Ray (1973). A Computer Perspective. Cambridge, Mass: Harvard University Press. p. 95. The date given, 1920, should be 1931 (see the Columbia Difference Tabulator web site)
  41. ^ Columbia Difference Tabulator
  42. ^ Columbia Alumni News, Vol.XXIII, No.11, December 11, 1931, p.1
  43. ^ New York Times, July 15, 1933, All subsidiaries of the International Business Machines Corporation in this county have been merged with the parent company to obtain efficient operation.
  44. ^ William Rodgers (1969). THINK: A Biography of the Watsons and IBM. p. 83. ISBN 9780297000235.
  45. ^ Rojas, Raul; Hashagen, Ulf (2000). The First Computers. MIT.
  46. ^ Campbell-Kelly, Martin & Aspray, William (2004). COMPUTER A History of the Information Machine. Westview. p. 59.((cite book)): CS1 maint: multiple names: authors list (link) The world's first for-profit calculating agency.
  47. ^ IBM 077 Collator
  48. ^ IBM Archive: Endicott card manufacturing
  49. ^ Equipements à cartes perforées (Punched cards machines) type A (GR) 1941-1950 Archived August 21, 2013, at the Wayback Machine
  50. ^ The IBM 602 Calculating Punch
  51. ^ IBM 603 Electronic Multiplier
  52. ^ IBM Archives: Endicott chronology 1941-1949
  53. ^ Bull Gamma 3 1952-1960 Archived July 27, 2013, at the Wayback Machine
  54. ^ a b Bull Gamma 3
  55. ^ Computer History Museum: Underwood Corporation
  56. ^ An Underwood-Samas sorter
  57. ^ Lee, J.A.L. (1995) Computer Pioneers, IEEE, p.557
  58. ^ Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991). IBM's 360 and early 370 systems. MIT Press. p. 34. ISBN 0-262-16123-0.
  59. ^ IBM Archives - DPD chronology
  60. ^ "IBM 1940 products brochure" (PDF).
  61. ^ Van Ness, Robert G. (1962). Principles of Punched Card Data Processing. Business Press. p. 10.
  62. ^ IBM Corporation (1959). IBM 1401 Data Processing System: From Control Panel to Stored Program (PDF). Order number F20-208.
  63. ^ Columbia University: The IBM 609 Calculator
  64. ^ a b IBM System 3
  65. ^ Dyson, George (1999) The Undead (Cardamation), Wired v.7.03
  66. ^ IBM 407 Accounting Machine
  67. ^ IBM Rochester chronology, page3
  68. ^ IBM Rochester chronology
  69. ^ IBM 029 Card Punch
  70. ^ IBM Punch-Card Plant Will Close, Joseph Perkins, The Washington Post, July 2, 1984
  71. ^ Visit to a working IBM 402 in Conroe, Texas
  72. ^ Conroe company still using computers museums want to put on display By Craig Hlavaty, Houston Chronicle, April 24, 2013
  73. ^ "Robert G. Swartz". December 19, 2011.
  74. ^ "Cardamation". ibm-main (Mailing list).
  75. ^ "California Tab Card Company". Archived from the original on 2016-01-25. Retrieved 2016-01-02.
  76. ^ a b c Gillespie, Cecil (1951). Accounting Systems: Procedures and Methods, Chapter 34: Equipment for Punched Card Accounting. Cowen Company, Boston. pp. 684–704.
  77. ^ (Cemach, 1951, pp 47-51)
  78. ^ Reference Manual, IBM 82, 83, and 84 Sorters. 1962. p. 25.
  79. ^ IBM 101 Electronic Statistical Machine - Reference Manal (PDF).
  80. ^ Cambell-Kelly, Martin; Aspray, William (2004). Computer: a history of the information machine (2 ed.). Basic Books. p. 42.
  81. ^ IBM (1949). The How and Why of IBM Mark Sensing (PDF). 52-5862-0. Retrieved 2019-08-19.
  82. ^ IBM Card Interpreters
  83. ^ IBM (1958). IBM 063 Card-Controlled Tape Punch (PDF). 224-5997-3.
  84. ^ IBM (1963). IBM Accounting Machine: 402, 403 and 419 Principles of Operation (PDF). 224-1614-13.
  85. ^ IBM (1956). IBM Reference Manual: Functional Wiring Principles (PDF). 22-6275-0.
  86. ^ Sutton, O. (1943). Machine Accounting for Small or Large Business. Macdonald & Evans. pp. 173–178.

Further reading

Note: Most IBM form numbers end with an edition number, a hyphen followed by one or two digits.

For Hollerith and Hollerith's early machines see: Herman Hollerith#Further reading

Punched card applications
The machines