Thank you for the correction. These were all memories that I hadn't thought about since the late 70's. Looking at the data book scans, the 1640 existed well before I spent any time there. I did remember the Glenrothes connection but not much more of the details. The point was that the designers weren't very likely to have any connection with a west coast company (SMS). This all was my first exposure to IC fab and design. Pretty interesting stuff for a kid like me who grew up in rural Wisconsin..