M.Sc. in mathematics, Northern Illinois University, 1969.
Ph.D. in computer science, University of Illinois, 1973.
Habilitation, University of Ulm, 1975.
Associate professor of computer science, University of Ulm, 1976-1987.
Professor of applied computer science, University of Osnabrück, 1988-2001.
Dean, department of mathematics and computer science, 1990-1991.
Visiting professor at the University of Illinois and at Rochester Institute of Technology.
Professor of computer science, Rochester Institute of Technology, 2001-present.
Editor of unix/mail
, Carl Hanser Verlag, 1991-1996.
Editor of Blaue Blätter
, Carl Hanser Verlag, 1997-1998.