IBM Statistical Tabulator

The IBM statistical tabulator is a specially built IBM numeric tabulator, designed to correlate test results and produce scientific tables. It read data from punched cards and from entries in any of ten 10-digit counters. It also multiplied numbers together, summed the products, and printed these out. Wiring of a plugboard determined the precise sequence of operations performed.

In the late 1920s, Benjamin Wood, a young psychologist at Columbia University, wrote to several manufacturers requesting assistance in the design of equipment for scoring psychological tests. James D. Watson, president of IBM, offered his assistance in the form of standard IBM machines and the help of IBM engineers in designing special models like this one. The Columbia machine, as it was sometimes called, was used both in test grading and in the production of astronomical tables, long a concern of scientists. Although it was soon superseded by other IBM equipment, its success inspired Wood to consider other inventions, particularly machines that scored tests directly from forms marked in pencil, eliminating the need for punch cards. Such machines and score sheets would be used for decades. More generally, scientific use of tabulating equipment spread throughout the United States.

The large black machine has gold trim. On the left side at the top is a card hopper that has approximately 75 cards. A metal plate with a handle holds the cards to the back of the hopper. In front of the hopper is a bank of five rows of counter control switches, with ten switches in each row. The columns of switches are numbered from 1 to 10. A flat metal plate extends in front of the switches. Below this is the receiver for the hopper. At the front are three switches, one labeled "COUNTER CLEARING" and another, "HOPPER STOP." Next to the bank of switches is a dial labeled "AUTO TRANSFER." Next to it is a push button, and then a lever that may be set on "TAB" of "LIST." Below this lever are six additional switches. In front of these switches are three push buttons covered with a metal cap.

The next unit to the right is the printer, which has a carriage 52 cm. wide. The printing mechanism is at the front. The carriage supports a roll of paper 36 cm. wide. Next to the printer is a row of dials that extends to the right side of the machine. Each dial is numbered from 1 to 9, with a blank space between 9 and 1. The dials are grouped in five groups of 11, and visible through five small glass windows.

There is a second, recessed row of dials below the first, with an additional five glass windows. Below these dials is a plugboard that runs from under the printer on the right side. The top rows of holes are for control switches, banks, adding brushes, etc. Below them is a 5x10 matrix of holes for "COUNTER NO 1," another for "COUNTER NO 2," etc. Below each of these matrices is a 6x10 matrix of holes. The leftmost is for "TOP COUNTER NO 1," "TOP COUNTER NO 2," etc. Ten sets of holes are for counters and ten for top counters. Thirty-seven cables are plugged into the plugboard.

References:

J. F. Brennan, The IBM Watson Laboratory at Columbia University: A History, Armonk, N.Y.: IBM Corporation, 1971, pp. 3–5.

D. A. Grier, When Computers Were Human, Princeton: Princeton University Press, 205, esp. pp. 190–193.

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