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Definition: 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." See punch card.

Programming a Card Punch Machine
This plugboard directed a machine to read the data in one card and punch the same holes in a blank card. Fields could be rearranged, and minor calculations could be performed. (Image courtesy of The Computer History Museum, www.computerhistory.org)

The Author of This Encyclopedia
In 1962, Alan Freedman was a Tabulating Technician, a fancy title for "punch card programmer." Proud to be photographed in "his" office at Pennsylvania Sales Tax, he is really at one end of a 40-foot room.

He Loves that Pose
Twenty years later, Freedman finally did have his own office two blocks from Penn Station in New York.