One Ken Shirriff's comment on reverse engineering CPUs makes a good point on system complexity. > For future reverse-engineering, I think the biggest problem w

One Ken Shirriff's comment on reverse engineering CPUs makes a good point on system complexity. > For future reverse-engineering, I think the biggest problem will be imaging. I can study processors up to about 1980 with an inexpensive microscope. But chips with two layers (or more) of metal are much harder to examine, because the metal layers block each other. And once transistors get too small for optical microscopes (1990s), you need an electron microscope, which is a much bigger investment. (Although there are hobbyists who have one.) > The other factor is understanding. A chip like the Z-80 is simple enough that one person can understand it completely. I doubt any single person at Intel understands everything about the Xeon, since it is so complex. And it's much harder to understand the chip from reverse engineering.