Papyrus: A Structured History Database for VLSI Design Flow Management

The trend of VLSI CAD tool development evolves towards functionally specialized, methodology-dependent and technologydependent. Confusion can easily arise during the design process because of the proliferation of CAD tools and the mammoth amounts of design data. This is aggravated by the fact that different CAD tools are usually created by different vendors with different interface styles. As a result, circuit designers have to mentally switch back and forth between various tools in order to get a task done. Previous VLSI design database systems deal only with the static aspect of VLSI design, i.e., the mpresentation and the StNCtUIt of design data. Almost no attention had been given to the dynamic aspect of VLSI design,.i.e., the execution of tools and the derivation of design data. In this paper, we argue why the dynamic aspect of VLSI design plays an important role in building an integrated design management system and propose a structured history model as a unified framework for managing data evolution and tool execution. The paper describes the implementation of a design history database system named Papyrus.