A knowledge-based system for multi-layer channel routing

A knowledge-based system is presented that uses the blackboard model of architecture, implemented in Prolog, and runs on the shared-memory multiprocessor Sequent Balance 8000. The inherent parallelism in this approach together with the OR-parallelism supported by the Argonne Prolog package has provided an ideal environment for such a development. The system utilizes a constraint-posting approach. Unlike existing systems, it views the number of available layers as yet another design constraint on the channel being routed, rendering it free from layer dependence, a restriction present in all existing systems. A number of important routing metrics including 100% routability, minimum routing area, minimum wire length, and minimum number of vias are considered simultaneously.<>