R1 and XCON at DEC

An expert system began configuring orders for VAX computers on Digital Equipment's production line, not in a laboratory but in daily work.

Why it matters

The first expert system that made money turned the field from a research pursuit into a commercial one.

John McDermott wrote it at Carnegie Mellon in the OPS5 rule language. It grew from about 750 rules to 2500; by 1986 it had processed 80,000 orders at 95 to 98 percent accuracy and, by DEC's estimate, saved some 25 million dollars a year. By 1985 corporate spending on expert systems passed a billion dollars a year. Maintaining the rule base turned out to cost more than writing it.

Event record

Event date

1980

Timeline date

Event date

Verification

Sources gathered automatically · September 17, 2026

Lines

ID

evt-0136

The system went into use at the DEC plant in Salem in 1980; development began in 1978 and the paper was given at AAAI-80 in August 1980.

Sources

primary R1: An Expert in the Computer Systems Domain
AAAI-80 · Published August 1980
primary R1 Revisited: Four Years in the Trenches (Judith Bachant, John McDermott)
AI Magazine, vol. 5, no. 3 (AAAI) · Published 1984

Related events

Earlier

Related The Art of Artificial Intelligence 1977
The system is a direct application of the knowledge principle stated in 1977.
Related MYCIN 1974
The same rule architecture, carried from medicine to hardware configuration.

Same period

Related The first AAAI conference 1980links to this record
R1, the system already running in production, was presented here.

Later

Related PROSPECTOR finds molybdenum 1982links to this record
The second expert system to produce a result outside the laboratory: XCON configured orders, PROSPECTOR pointed to ore.
Related CATS-1: rules for repairing locomotives 1983links to this record
Both records concern a rule-based expert system taken out of the laboratory into a company's operations: configuring VAX orders in 1980, troubleshooting locomotives in 1983.
Related The Lisp machine market collapses 1987links to this record
The market XCON opened collapsed not over the quality of the systems but over the cost of the hardware under them.
Related Authorizer's Assistant: an expert system decides on credit 1988links to this record
Both records concern a rule-based expert system in a large company's daily work: configuring VAX orders at DEC in 1980, credit decisions at American Express in 1988.
Related DART: the scheduler that repaid thirty years 1991links to this record
The same kind of system as XCON at DEC, put into a headquarters during a war.