"All of this from a man who was the son of a millwright, only in America."

I wondered, What exactly is a millwright? It's one of those older words that everyone once knew the definition of. Apparently, they set up and integrate heavy equipment in mills and factories:

http://www.bls.gov/oco/ocos190.htm

http://www.guymturner.com/rigging-millwright/equipment-proje...

So it looks like they are skilled, blue collar, mechanical/industrial hackers. Greg Linden sees his father's programming proclivities in himself and his son; perhaps the tendency extended back to his grandfather, too.