XCON was the first commercial expert system, deployed by Digital Equipment Corporation in 1980.
Carnegie Mellon researcher John McDermott developed XCON, originally called R1, to help configure Digital Equipment Corporation’s VAX computer systems. The program used production rules to match customer orders with compatible hardware components and to identify configuration problems.
Before XCON, configuring a large computer system required substantial manual work by specialists. The expert system encoded many of the company’s configuration rules, making the process faster and reducing errors. Digital began using it commercially around 1980, and the system was later expanded substantially.
XCON is often confused with earlier research systems such as DENDRAL and MYCIN. DENDRAL analyzed chemical structures, while MYCIN offered advice about bacterial infections. XCON’s importance came from demonstrating that rule-based AI could deliver practical business value in a large commercial operation.