reikäkorttitekniikka

Reikäkorttitekniikka refers to the use of punched cards as a medium for storing and processing data. Originating in the 19th century, punched cards played a pivotal role in the early development of computing. Data was represented by the presence or absence of holes in specific positions on a card. These holes were then read by mechanical or optical devices, translating them into machine-readable information.

The invention of the Jacquard loom in 1801, which used punched cards to control weaving patterns, is an early example of this technology. Later, Herman Hollerith developed a tabulating machine using punched cards for the 1890 U.S. Census, significantly speeding up the data processing. This led to the formation of the Tabulating Machine Company, a precursor to IBM.

Throughout the first half of the 20th century, punched cards were the dominant form of data storage and input for business machines, early computers, and electronic calculators. Programs and data were punched onto separate decks of cards. Specialized machines like keypunches were used to create these cards, and other machines were used for sorting, collating, and tabulating the information.

While revolutionary for its time, reikäkorttitekniikka had limitations. Cards were bulky, prone to damage, and had a limited storage capacity. The process of manually handling and feeding cards was also labor-intensive and slow. By the late 1960s and 1970s, magnetic tape, disks, and eventually other digital storage media began to replace punched cards as computing technology advanced. The last major use of punched cards in the U.S. Congress ended in 2011.