Aperture card

An aperture card is a card with a small hole in the middle. It is used to store information that can be read with a machine. The small hole is called the aperture, and it is used to let a machine read the information on the card. Inside the card, there are strips of magnetic tape or film that contain instructions or other information. When these cards are put into a special machine, the machine can read the information inside the hole, and act on it. Apertures cards are used in many different types of activities, from entering data into computers to controlling machines in factories.