Cleaning up some stuff, found photo copies of these three articles, so I scanned them, but then found cleaner versions from circuitcellar.com with a little help of the wayback machine. I'm not sure where to put them. Here seem most appropriate. They are all written by Ed Nisley of I believe of https://softsolder.com/
How the PC Keyboard Got its Bits
Journey to the Protected Land: The Mystery of Scan Code Set 3
Journey to the Protected Land: Of Characters and Keystrokes
Thanks Ed, three nicely written articles.