keypunch

Keypunch refers to the process of encoding information onto a medium such as punched cards or punched tape. This was a common method of data entry and input for early computers and data processing machines. A keypunch machine, also known as a card punch, was operated by a person who would strike keys corresponding to letters, numbers, or special characters. Each keystroke would then create a physical hole in a specific location on a card or tape, representing the entered data.

These holes were read by mechanical or optical sensors in subsequent machines, such as a card reader or a computer's input device. The pattern of holes determined the character or command being processed. Keypunching was a labor-intensive process, requiring trained operators to accurately transcribe information. The widespread adoption of magnetic storage media and direct data entry systems, such as keyboards connected to computers, led to the gradual obsolescence of keypunching. While no longer a primary method of data entry, the concept of encoding information through distinct marks or patterns remains fundamental to digital technology.