R1（后来被称为XCON，eXpert CONfigurer的所写，意为专家设置）进程是基于生产规则的系统，由卡内基梅隆大学的John P. McDermott在1978年用OPS5开发。其目的是按照用户的需求，帮助DEC为VAX型计算机系统自动选择组件。XCON的开发继承了两个之前用FORTRAN语言和BASIC语言未成功的尝试完成了一个专家系统。

在1980年，XCON最初被用于DEC位于新罕布什尔州萨利姆的工厂。最终它有了大约2500条规则。截止至1986年，它一共处理了80,000条指令，准确率达到95-98%。据估计，通过减少当技师出错时送给客户的组件、加速组装流程、和增加客户满意度，它每年为DEC节省了两千五百万美元。

The R1 (internally called XCON, for eXpert CONfigurer) program was a production-rule-based system written in OPS5 by John P. McDermott of CMU in 1978 to assist in the ordering of DEC's VAX computer systems by automatically selecting the computer system components based on the customer's requirements. The development of XCON followed two previous unsuccessful efforts to write an expert system for this task, in FORTRAN and BASIC.