Early method of data storage used with early computers. Punch cards also known as Hollerith cards and IBM cards are paper cards containing several punched holes that were punched by hand or machine to represent data. These cards allowed companies to store and access information by entering the card into the computer. The picture is an example of a punch card.
Punch cards are known to be used as early as 1725 for controlling textile looms. The cards were later used to store and search for information in 1832 by Semen Korsakov. Later in 1890, Herman Hollerith developed a method for machines to record and store information on punch cards to be used for the US census. He later formed the company we know as IBM.
Punch cards were the primary method of storing and retrieving data in the early 1900s, and began being replaced by other methods in the 1960s and today are rarely used.