TITLE: Index-Card Computing AUTHOR: Eugene Wallingford DATE: July 31, 2004 4:12 PM DESC: a teaching example for associate memory ----- BODY: This story is a wonderful illustration of the idea of associative memory:
I remember my grandad, who worked in the police, telling me how they used to keep details of criminals on filing cards. On the edge of each card there were a number of punched holes, some punched right the way to the edge. Each punched hole corresponded to some fact about the person -- whether they were a burglar or a mugger or things like that. So, if you wanted to pick out all the burglars, you'd take a metal skewer and slide it in through the appropriate hole and lift it up. All the cards whose hole had been punched right to the edge (non-burglars) would stay behind, whilst all the relevant ones would get lifted up.
I found this story in an article on DNA-based computing at Andrew Birkett's blog. If you've ever wondered about how biocomputing can work, read this article! It's really neat -- yet another example of how Mother Nature can do intractable search using massive replication and parallelism. -----