core-logic clock / was Re: TTL homebrew CPUs

William Donzelli wrote: Chapter 7 of "IBM's Early Computers" by Bashe, Johnson, Palmer, and Pugh is all about IBM's experience in developing their core memory expertise and getting it into production, along with some of the patent intrigue, core memory history, and avenues that were explored and abandoned. This is all written from IBM's perspective. After reading this chapter, it disabused me of the meme that Wang invented core memory. Others had proposed using magnetic rings before Wang. IBM even had done some experimenting with them before hearing of Wang's results at Harvard, which were far more advanced than what IBM had done to that point. Munro Haynes read Wang's paper and started his own experiments at the University of Illinois. It was Hayes who figured out coincident current switching, which makes addressing the cores a whole lot more pratical. Haynes later joined IBM. MIT too worked on practical core memory, and there was some back and forth with IBM about it. I won't replay the whole chapter, but the main points are two: (1) like many inventions, there wasn't a single father, rather a concurrent development by many parties that were sometimes aware of the work of the others, sometimes not (2) IBM didn't pay through the nose for Wang's patent; they got Wang's patent for "several hundred thousand dollars" according to the book. IBM payed through the nose (in their estimation) for rights to core memory technology patented by Jay Forrester at MIT (through MIT's patent management company). MIT was insisting on royalties of two cents per bit (core). Their tussle went on for years, and in the end IBM paid out a one time $13M fee for the rights to the Forrester patent. By that time (1964), IBM was using more than one billion cores per year. The chapter has a lot of other really interesting detail and is worth the read.