OPS[2]

Official Production System

Charles L. Forgy, Carnegie Mellon University, 1970

The first production-system (i.e. a rule-based forward-chaining) programming language, used for building expert systems. It was written originally in Franz Lisp, and later ported to other LISP dialects.

OPS4

OPS5

The 1977 version, publicly available from the author. It was first implemented in LISP, and later in BLISS.

Programming Expert Systems in OPS5: An Introduction to Rule-Based Programming, Lee Brownston et al, Addison-Wesley, 1985.

An OPS5 Primer: Introduction to Rule-Based Expert Systems, Porter D. Sherman et al, Prentice Hall, 1990. Comes with OPS5 for MS-DOS.

OPS5+

OPS83

Inference Engine Tech, Cambridge MA.

C5

An OPS5 implementation in C.

"Rule-Based Programming in the Unix System", G. T. Vesonder, AT&T Technical Journal 67(1), 1988.