1506 nix nix

Actually, this phrase did finally get an answer. I read it in a Comic’s Buyers Guide years ago.
1506 was the apartment number of a friend of Holman’s who was a womanizer. the Nix Nix was his way of warning women away from that guy’s apartment.

A link to the Staff Report is appreciated. What’s the origin of “notary sojac”? 03-Apr-2001

Another note on this:

This, of course, is a tradition that continues to this day in software documentation, books, examples, and actual code.