I don't recognise the name Herb Sutter.
I don't know him.
I know him not.
What's the difference?
In terms of meaning, there is no difference.
"I know him not" is an archaic, or out of fashion, way of saying it. It wouldn't be incorrect to say that, even now, and some people might do so out of stylistic reasons (or something else). Everyone will understand. However, it's the old way of saying it, and most people wouldn't say it that way.