Before Computers—The Tab Card Epoch

by Charles Bovaird

Before computers there were tabulators. Before tabulators there were calculators. Before calculators there were analog calculators. Before analog calculators computation was performed using writing instruments and mental calculations. An example is the (25.5” x 14”). Accountant’s 21 column WORKSHEET illustrated here

Tabulating machines relied on input data in the form of punched cards. These electromechanical machines used electrical relays to control the card transport mechanism, mechanical storage devices, and the printing mechanics.

A special purpose electromechanical calculator example is The Turing Bombe used for code breaking (crypto-analysis) during WWII.

Other mechanical calculators used in business during the tabulating epoch are the Comptometer, the Marchant, and the Monroe calculating machines.

Examples of analog calculators are the slide rule, astrolabe, abacus, logarithmic tables, and Artillery firing tables.

Examples of writing instruments, paper, pen, chalk, blackboards, papyrus, and blackboards.

Accounting students in the 50’s used 14 and 21 column accounting forms (illustrated) also referred to as Tab Sheets or worksheets for managing account data. This involved cross posting account values into appropriate column categories, manually adding up the columns, validating the column sums, and resolving any posting or addition errors. Tabulators and calculators were not available in the classroom. Slide rules were used in some courses. Education in the use of logarithmic tables was standard.

Treating each of these epochs, history shows there is overlap between one epoch and the next.

This article will focus in on the tabulator epoch experienced by the author and defined by the IBM tabulating card. During this epoch other companies were competing in the commercial business tabulator market though IBM was dominant.

The tabulator epoch began about 1860 and was initiated by Herman Hollerith's invention of the tabulating machine used to process data for the 1890 U.S. Census.

The tabulator epoch ended about 1968 when the punched card equipment was no longer used inside IBM. The punched cards demise started about 1950 with the introduction of large commercial electronic computers using vacuum tube technology and magnetic tape media. During this period source data was read from punched cards and written on magnetic tape. Later, punched cards were displaced by typewriter keyboard devices controlled to write on to magnetic tapes. The magnetic tapes were then used as input to computers. In some cases punched tape was used. Typewriter keyboard devices were later displaced by monitor/keyboard devices (IBM 3270).

Thee IBM punchcard measured 3 1/4" x 7 3/8". It came 2000 cards to a box. The card columns were numbered left to right one through 80. The card rows were identified top to bottom as 12, 11, 0,1,2,3,4,5,6,7,8,9 respectively.

The IBM tab card illustrated here was found stapled to the bottom of a furniture cabinet. They could be ordered with printing tied to specific job processes. The card-punch machine could print the characters that represented the columnar punched holes. This card was used on IBM 360 machines and the punched holes were coded for alphanumeric interpretation. The 12 rows from top to bottom were 12, 11, 0 ,1, 2, 3, 4, 5, 6, 7, 8, 9. The letters A to I used a 12 punch, J to S and 11 punch, T to Z a 0 punch. Special characters and punctuation required three holes per column. Cards had the top left corner cut to assist in card orientation relative to other cards in a deck of cards.

Tabulating operations required processing an ordered sequence of cards. To prepare the cards for tabulation required the use of card punches, card sorters, and card collators.

Throughout the tabulating epoch machines improved in card processing speed and card handling reliability. A tabulating job could require one or more card decks with some jobs requiring thousands of cards. Card decks were manually transported between card punching machines, sorters, collators, and tabulator. The output of a tabulator was a series of printed reports. Many looked like a current spreadsheets or database reports. The machines, as a group, were referred to as Electronic Accounting Machines (EAM).

Sorting machines

A deck of tabulating cards had to be run through the sorter column by column. If there were multiple punches in a column it had to be run through the machine has many times as there were punches in that column. To control this each run required setting some tabs to select the appropriate row selection settings. The operator had to collect the cards from the individual hoppers in the proper sequence and place them in holding racks above the sorter in such a way that the order was maintained. The quality of the process required skilled operators and a high degree of cooperation between individuals on the data processing floor as well as between operating shifts. Any error introduced by card handling or machine error would likely require starting the sort over from the beginning.

Collating machines

Collating machines were used to merge two sequenced card decks into one. The collator had a wired plug board to control the field selections and merge sequence rules. Different plugboards were used for each unique collating process. The correct board had to be placed in the collator before running a job related collating sequence.

Tabulating machines

Tabulating machines were the most complex. They had a card reader, a wired plug-board control panel, a mechanical printing mechanism, and banks of relays. The typical tabulator could handle paper of various widths up to 120 characters across. Tabulating totals and logic were managed by wiring the plug board control panel. Up to five-part carbon paper could be used. Printing was accomplished by moving the pin feed paper into the proper vertical position where a row of print could occur. For each column the appropriate type slug would be aligned with each print hammer position. Each hammer would smash the paper into an inked ribbon and into the type slug. Multiple hammers firing to create a line of print was quite noisy. Multiple tabulators running in the same room sounded like a foundry.

Additional background on tabulating machines can be found at:
http://en.wikipedia.org/wiki/Tabulating_machine and http://en.wikipedia.org/wiki/IBM_407.

It is important to note that during the tabulation card epoch customers bought the use of machines by rental agreements. Machine repairs were included in the rental cost however since machine down situations could adversely affect processing schedules and costs, the reliability of installed machines and the quality of the repair effort was a key value to both the customer and the supplier. In IBM employees who repaired machines were called “Customer Engineers” to identify the true scope of their responsibilities.

Punched card systems played a key role in the 1890 US census, the implementation of the Social Security system, and World War II armed forces supplies management. Written lists or a deck of punched cards were the data storage device of this epoch.

Next – the vacuum tube computer epoch



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