Punched cards were widely used in the 20th century, where unit record machines, organized into data processing systems, used punched cards for data input, output, and storage. The IBM 12-row/80-column punched card format came to dominate the industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and data.
Punched cards were widely used in the 20th century where unit record machines organized into data processing systems used punched cards for data input output and storage The IBM 12-row/80-column punched card format came to dominate the industry Many early digital computers used punched cards as the primary medium for input of both computer programs and data