 IBM, Hewlett-Packard, SDA Systems and ECAD (now Cadence Design Systems), High Level Design Systems, and many other companies developed EDA specific databases over the last 20 years, and these continue to be the basis of IC-design systems today.Many of these systems took ideas from university research and successfully productized them.Most of the mature design databases have evolved to the point where they can represent netlist data, layout data, and the ties between the two.