OPS5, one of the widely used production system languages, offers many interesting facilities like structured representation of facts of a domain, nonmonotonic deduction etc. However, it suffers from some major drawbacks such as its inability to reason with revocable actions and handle dead ends and domain constraint violations. In this article, we present a new OPS architecture (called OPS91) which uses the RMS methodology to maintain reasons for actions performed, as a partial solution to the above problems. We show that the new architecture can solve a wider class of problems and hence, is a better production system model for problem solving. The OPS91 architecture is implemented in common LISP on a MicroVaxII work-static n and is currently being tested. © 1991 IEEE.