Part 5/8:
The Mechanics of Punch Card Programming
By the early 20th century, IBM was producing up to 10 million blank punch cards daily. The cards had a specific design, usually featuring 80 columns and 12 rows for data input. Programmers wrote code on special coding sheets before transferring it to punch cards using key punch machines—a laborious process that required precision and care.
Early programming languages such as FORTRAN, COBOL, and assembly language emerged to help programmers communicate with machines using more intuitive terms. Each punch card represented one line of code, and a program could consist of hundreds to thousands of such cards.