Q & A with Sydney Ann Holt, a layout designer of the 6502 microprocessor

My job was the same as Harry Bawcom and Mike Janes. We were given the logic drawings from Bill Mensch and Ray Hirt and etc, and turned them into the drawing you see in the picture from the Electrical Engineering Times article from 1975.

To do this, we drew them in pieces on big sheets of mylar that fit together like a puzzle. In order to do a careful logic to layout check we taped all the pieces together on the floor and crawled around on it to trace out the lines. The drawings were then digitized into layers so masks could be made from them.

I remember that once, one of the guys took off his shoes and was on the mylar checking when it was discovered his socks were damp and his toes were erasing the drawing as he moved along. Fortunately, it was caught very soon so the rework was minimal. We had a good laugh over it.

In order to design a microprocessor without a computer, it first had to be inhabited at human scale. This reminds me of the Minecraft projects that build fully-functional CPUs, the sheer scale of those circuits, and they way players fly through them.