In the early days of computers, computer terminals did not exist. You entered programs and data into computers via punched cards. Each card had one line of computer code. The picture above shows the key punch machines which were used to punch the holes in the cards. The blank cards are entered into the top of the machine, and as you type on the key board holes are punched into the cards. You end up with a stack of cards, and those cards are then run through the computers card reader to enter the program into the computer. These were still in use in the 1980's, and when I learned to program at the University of Texas, it was using card punch machines similar to the ones in this picture.