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.
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 of This Encyclopedia
In 1962, Alan Freedman was promoted from Tabulating Operator to Tabulating Technician, which meant he programmed the equipment by wiring plugboards. Proud to have a photo taken in "his" office at Pennsylvania Sales Tax, he is actually at one end of a 40-foot room. His job still required moving tons of punch cards in and out of machines. See punch card
He Loves that Pose
Twenty years later, Freedman finally did have his own office two blocks from Penn Station in New York, where he and his wife founded The Computer Language Company.