KQML Software Architectures

KQML was not defined by a single research group for a particular project. It was created by a committee of representatives from different projects, all of which were concerned with managing distributed implementations of systems. One was a distributed collaboration of expert systems in the planning and scheduling domain. Another was concerned with problem decomposition and distribution in the CAD/CAM domain. A common concern was the management of a collection of cooperating processes and the simplification of the programming requirements for implementing a system of this type. However, the groups did not share a common communication architecture. As a result, KQML does not dictate a particular system architecture, and several different systems have evolved.

Our group has two implementations of KQML. One is written in Common Lisp, the other in C. Both are fully interoperable and are frequently used together. The design of these implementations was motivated by the need to integrate a variety of preexisting expert systems into a collaborating group of processes. Most of the systems involved were never designed to operate in a communication oriented environment. The design is built around two specialized programs, a router and a facilitator, and a library of interface routines, called a KRIL.

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