An EDA database is a database specialized for the purpose of electronic design automation. These application specific databases are required because general purpose databases have historically not provided enough performance for EDA applications. In examining EDA design databases, it is useful to look at EDA tool architecture, to determine which parts are to be considered part of the design database, and which parts are the application levels. In addition to the database itself, many other components are needed for a useful EDA application. Associated with a database are one or more language systems (which, although not directly part of the database, are used by EDA applications such as parameterized cells and user scripts). On top of the database are built the algorithmic engines within the tool (such as timing, placement, routing, or simulation engines ), and the highest level represents the applications built from these component blocks, such as floorplanning. The scope of the design database includes the actual design, library information, technology information, and the set of translators to and from external formats such as Verilog and GDSII. Mature design databases Many instances of mature design databases exist in the EDA industry, both as a basis for commercial EDA tools as well as proprietary EDA tools developed by the CAD groups of major electronics companies. 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. They are hierarchical to allow for reuse and smaller designs. They can support styles of layout from digital through pure analog and many styles of mixed-signal design. Current design databases The OpenAccess design database Given the importance of a common design database in the EDA industry, the OpenAccess Coalition has been formed to develop, deploy, and support an open-sourced EDA design database with shared control. The data model presented in the OA DB provides a unified model that currently extends from structural RTL through GDSII-level mask data, and now into the reticle and wafer space. It provides a rich enough capability to support digital, analog, and mixed-signal design