Test: shared problems and shared solutions

Test is a universal problem-common to all sectors of the electronics and IT industries. However, significantly different solutions have been required in the past-dictated by factors including the complexity of the product under test and the extent to which features to support test could economically be designed into the product. The latter was a particular problem at the integrated circuit level where, for a long time, the amount of circuitry available within each component was limited. Today, what were once large and complex systems are now single integrated circuits. It has become both economical and technically desirable to deploy test approaches that were once relevant only to, say, mainframe computers to the testing of circuit boards, integrated circuits, and even parts of integrated circuits. Put simply, "systems on silicon" demand system-oriented test approaches. The goal of this article is to illustrate this point and to highlight the commonalities between what at first glance may appear to be different approaches to test applied at different levels of integration.