Yes, I did Rexchess with Don Dailey in the late 1980s before Socrates, although as is the case with Rybka, I did not write actual program code, just chess algorithms, numerical values for terms, and the opening book. But my involvement with computer chess goes way back before that. In 1967, as an M.I.T. student, I was the chess adviser/tester/book author for "MacHack", the first program to compete in human chess tournaments (it earned a rating in the mid 1500s).