Model-based diagnosis of hardware designs

The state of the art in hardware design is the use of hardware description languages such as VHDL. The designs are tested by simulating them and comparing their output to that prescribed by the specification. A significant part of the design effort is spent on detecting unacceptable deviations from this specification and subsequently localizing the sources of such faults. In this paper, we describe an approach to employ model-based diagnosis for fault detection and localization in very large VHDL programs, by automatically generating the diagnosis model from the VHDL code and using observations about the program behavior to derive possible fault locations from the model. In order to achieve sufficient performance for practical applicability, we have developed a representation that provides a highly abstracted view of programs and faults, but is sufficiently detailed to yield substantial reductions in the fault localization costs when compared to the current manpower-intensive approach. The implementation in conjunction with the knowledge representation is designed with openness in mind in order to facilitate use of the highly optimized simulation tools available. (C) 1999 Elsevier Science B.V. All rights reserved.