An annotation system for VLSI design

Two areas are identified in which automatic schemes can be developed to alleviate the integration problem in developing an electronic system for CAD tools: consistency maintenance and annotation. The authors develop an annotation facility that supports annotations at different levels of details: object-level documentation, characteristics summary, and sub-object annotations. A novel sub-object annotation model called the transparency model is developed that allows arbitrary annotations to be attached to arbitrary portions of the design objects. Furthermore, this annotation facility can be used to annotate objects of various design representations. A monitor subsystem that can detect possible inconsistency between the designs and the annotations is built into the annotation system to notify users of potentially stale annotations