At the same time, he switched from a paperstrip to punched cards. (Making the cards the same size as dollar bills meant that existing storage cabinets could be used.) By clever wiring of the tabulating machine, it was possible to count the number of cards with particular combinations of attributes.
We were using typewriters, where the state of the art way to correct a typo was to backspace and put a strip of white paper behind the key and retype the word.
Davis said it's time to do away with the old fashioned paper-and-pencil flight strip markings that controllers in towers have been using to track aircraft for decades.
Seeing the drawing in person, one is confronted with its fragility and physicality: The sheet comprises two pieces of paper, glued together with a strip that runs right through the center.