XCON
In plain wordsA rule-based program used from 1980 by the computer maker Digital Equipment Corporation to work out which parts each customer's computer order needed. It was the first big commercial success of expert systems.
A production-rule expert systemexpert system, n.: A program that stores a human specialist's know-how as many if–then rules and uses them to give advice or make decisions in a narrow field, such as diagnosing infections or configuring computers. that configured orders for Digital Equipment Corporation's VAX computers: it checked that requested components were compatible, added missing parts such as cables and power supplies, and specified how cabinets and modules should be laid out. Written in the OPS5 production systemproduction system, n.: A program built from many 'if this, then do that' rules plus a memory of current facts; it repeatedly finds a rule whose 'if' part matches and carries out its 'then' part. language, it worked forward from the order through a fixed sequence of subtasks, firing whichever rule matched the current state rather than searching among alternatives. Put into routine use at DEC in 1980, it grew from several hundred rules to many thousands and handled tens of thousands of orders a year with high accuracy, and DEC credited it with savings in the tens of millions of dollars annually. Its mounting maintenance burden also illustrated the upkeep costs that later undermined the expert-system boom.
XCON became the standard evidence for the claim that expert systems could pay their way.
Origin
Developed by John McDermott at Carnegie Mellon University from 1978 under the name R1, which he explained with a joke about having recently become a knowledge engineer. Renamed XCON (eXpert CONfigurer) when DEC took over its development.
Related
- expert systemexpert system, n.: A program that stores a human specialist's know-how as many if–then rules and uses them to give advice or make decisions in a narrow field, such as diagnosing infections or configuring computers.
- production systemproduction system, n.: A program built from many 'if this, then do that' rules plus a memory of current facts; it repeatedly finds a rule whose 'if' part matches and carries out its 'then' part.
- forward chainingforward chaining, n.: A way of reasoning that starts from known facts and keeps applying rules to them, adding each new conclusion, until it reaches an answer or nothing new can be concluded.
- MYCINMYCIN, prop. n.: A 1970s Stanford program that advised doctors on blood infections and antibiotics by applying hundreds of if–then rules from specialists. It performed about as well as experts but was never used on patients.
- AI winterAI winter, n.: A slump in which disappointment over AI's unmet promises leads governments and companies to pull back money and attention. Historians count two big ones: one in the 1970s and one starting in the late 1980s.
- rule-based systemrule-based system, n.: A computer system that makes decisions by following a list of 'if… then…' rules written by people, rather than by learning from examples.
Sources
- McDermott, J. (1982). R1: A Rule-Based Configurer of Computer Systems. Artificial Intelligence 19(1), 39–88.
Mentioned in
expert systemexpert system, n.: A program that stores a human specialist's know-how as many if–then rules and uses them to give advice or make decisions in a narrow field, such as diagnosing infections or configuring computers., rule-based systemrule-based system, n.: A computer system that makes decisions by following a list of 'if… then…' rules written by people, rather than by learning from examples.