Old and new punched cards

Dayton headquarters

Punched cards
IBM announced on December 1, 1964, that round corner cards would be a regular feature on its general purpose punched cards. Round corner cards, announced a year earlier by IBM, accounted for more than two-thirds of the company's punched card volume (measured in the tens of billions a year) by 1965. Virtually all punched cards had been manufactured with square corners since they were first used in the 1890 census.