plugboard

A board containing a matrix of sockets used to program a machine. Plugboards were widely used in punch card tabulating machines and early computers and were the predecessor to software programming. For example, each wire in the board directs a column of data from its source column to its destination which could be a print column or a card column to be punched. A wire could also function as a switch by closing a circuit. Complicated programs looked like "mounds of spaghetti."

Plugboard for a Card Punch

This plugboard directed a machine to take the data from one set of punch cards and punch it into another. Fields could be rearranged, and minor calculations could be performed. (Image courtesy of The Computer History Museum, www.computerhistory.org)

The Author in 1962

Alan Freedman, author of this Encyclopedia, learned data processing the hard way: by carrying the data on his back. Trays of punch cards were heavy. As a "Tabulating Technician III" in this 1962 photo at the Pennsylvania Sales Tax division in Harrisburg, he not only wired the boards, but shoved millions of cards through the machines.

Four Decades Later

Forty years later, the data may be lighter, but the processing is heavier. Freedman is involved in every facet of this publication, including writing the definitions, drawing many of the diagrams, designing the user interface and collaborating on the various hosting systems the company has developed.