Glad to be of help. I find this era fascinating. I think it's obscure because it solves a problem we don't really have. We take computers for granted, and most

Glad to be of help. I find this era fascinating. I think it's obscure because it solves a problem we don't really have. We take computers for granted, and mostly group solutions into "with a computer" and "manually" (with pencil and paper), because that's what we are used to. We aren't used to thinking about mechanical solutions, and clever indexing schemes for how to organize piles of paper. Before I started on this research, I had never heard of edge-notched cards, much less appreciated coding schemes that minimize the number of manual needle insertions needed to search a deck. I've been trying to understand why superimposed coding systems did not reach the modern world. The principles behind it really helped me understand how some modern techniques work, but those modern techniques are ad hoc. Already by 1974 superimposed coding was considered an 'old technique.' I quote from "The Large Data Base File Structure Dilemma", http://dx.doi.org/10.1021/ci60001a005 http://dx.doi.org/10.1021/ci60001a005 : > The second solution to the dilemma, suggested in Figure 7, is sequential search. This may appear to be a throwback, particularly within the framework of on-line systems, but it should be noted that the speed of the CPU combined with the extremely high data transfer rate from secondary storage of third and fourth generation computers has reached a point where one might profitably reexamine the potential of sequential processing. I interpret this and similar articles to mean that the older techniques weren't a good fit for the then-current computer architectures. After two generations of disuse, institutional memory fades. And reading the old literature doesn't help if you read it through the eyes of people with 1GHz processors - many of the driving problems are trivially brute-forceable. I read "Punched Cards" in part to get a sense of what it was like to think in those old terms. Now I want to acquire edge-notched cards and physically experience it. But no one sells those cards any more, and haven't for decades. There's a lovely article about this 'dead medium' at http://kk.org/thetechnium/one-dead-media/ http://kk.org/thetechnium/one-dead-media/ . Luckily, we also have new solutions. This modern crafting era has machines that can mark and cut paper product with ease. I think it would be possible to make each card "from scratch" on the computer, rather than the old school style of using large machinery to cut and print a template, followed by manually content addition.