80-column punch card: IBM, circa 1970
IBM tabulating machines, a direct forerunner of computers, used this standard 80-column punch card beginning in 1928. The bottom ten rows are labeled with digits; the top two rows are unlabeled and are used in an alphanumeric character code first standardized by IBM in 1931. Cards were in use for all kinds of tabulating machines far before they were used for computer data and programs (e.g., time cards). In 1937, IBM had 32 presses at work printing, cutting and stacking five to ten million punch cards a day. They were even used as legal documents such as U.S. Government checks. Two decades later, IBM computers would interpret “holes or no holes” in punch cards as zeroes and ones, the basic language of digital code. Today, punch cards are obsolete, but 50 years ago they were the tangible sign of a computer revolution that would eventually sweep the world.