Hi Greg! Now I remember where I had seen your name before. Perhaps I read your deposition (if there was one)? Or just on a list of LTC staffers?
To do justice to your post and all your questions would require too much writing and thinking, so I'll just clarify a few things.
1. The breach of contract part of the case wasn't about IBM putting System V code into Linux. It was about IBM putting IBM code into Linux, and McKinney's RCU was a good example. Nobody thought this was System V code or that it had anything at all to do with AT&T. I think the LTC was staffed with a lot of former Dynix (not sure I remember the name correctly) people, right? And they put some of Dynix into Linux.
2. Examples that got widely talked about, such as malloc, were not good examples of what the copyright case was about. As I said, I didn't work on it, but I got briefed sometimes. This is an example of what I was talking about: People thinking they knew what the issues were based on the issues that they knew about. 99% of the evidence was sealed.
3. JFS (1 or 2, don't remember) as I recall was a tricky case. Something like what you say, that it was developed in a clean room, but then put into AIX and subsequently into Linux. If any AIXness got into Linux, then it was also (like RCU) a case of IBM putting into Linux code that had come from a System V derivative.
I would like to make it clear to the whole TUHS community that I personally am not arguing one way or another about the ethics or legality of any of this stuff. The contract between IBM and AT&T didn't even make sense.
I think the contribution that LTC made to Linux was enormous, not least because it told the world that Linux was ready for prime time (e.g., mission critical server farms).
Marc