Wafer-Scale Testing/Design for Testability

Testing is an integral part of the production and operation of computer systems, whether they are implemented in WS I or in more traditional technologies. As digital systems become more complex, they are characterized by more internal circuitry per I/O line and larger internal state spaces. This makes testing complex systems as integrated units very difficult. The testing problem can be made more tractable by partitioning them into subsystems that can be tested separately. With very complex integrated systems, this partitioning requires either design for testability, built-in self test (BIST) techniques, or both, since otherwise the entire integrated system would have to be tested through its inputs and outputs as a monolithic unit.