>Leibniz (inventor of calculus) used this method very heavily in his own work. Before computers--and even into the 1960s--it was the most important way of automating data processing. Back then, you used cards that had a row of either holes or notches along one edge, and selected matching cards from a stack by inserting a rod through the stack at a selected spot, and lifting.
Hey, do you have a reference for that? I've been doing some research into Leibniz's calculators, and I've been finding few sources.
There is quite a lot about Leibniz's calculating machine designs on Wikipedia.
I think I found out about Leibniz's bitwise activities in Neal Stephenson's Quicksilver, but he invented the modern notions of both sets and digital logic, according to Wikipedia. He would have used the cards in catalogging libraries.
Hey, do you have a reference for that? I've been doing some research into Leibniz's calculators, and I've been finding few sources.