Do not fold, spindle or mutilate. This stern warning, found on the punch cards ubiquitous in the mid-20th century, is etched in the memories of a generation. Recite it to any IT pro over a certain age and you\u2019ll elicit stories of summers spent collating wayward cards or recent trips to the Smithsonian to see a card sorter categorized as a museum relic. F. Warren McFarlan, now a professor at Harvard Business School, remembers the nerve-jangling process of completing his doctorate in MIS in 1965. The 10,000-line Fortran program he had created was stored on thousands of punch cards. "All you needed was one card upside down, or you dropped one on the floor or a card jammed in the machine, and life became very exciting and complicated," he says.Punch cards allowed information to be taken off a sheet of paper and manipulated physically and electronically. Developed by American inventor Herman Hollerith, who was looking for a way to speed up the job of the U.S. Census Bureau in 1890, the cards were inspired in part by those used to control patterns on the Jacquard textile loom. Hollerith\u2019s cards contained data arranged by combinations of perforations; each card could store as many as 80 variables. The punched cards were then fed into a tabulating machine. The company Hollerith later founded to make these machines eventually became IBM. The punch card retreated into the background decades ago, but occasionally evidence appears that proves it is not yet extinct (two words: hanging chads). Says McFarlan, "Deep in the inner nooks of public service and backward organizations, traces of this technology live on today." Feeling nostalgic about a favorite technology? Tell Features Editor Sara Shay at email@example.com.