START: System Testability Analysis and Research Tool

A brief overview of the Systems Testability Analysis and Research Tool (START) software package for automatic test sequencing and testability analysis of complex hierarchically described modular systems is presented. It consists of algorithms based on information theory, heuristic search, and graph theory to solve various facets of the test sequencing and testability analysis problems. A system is modeled in the failure space as a hierarchical directed graph with nodes denoting modules and test points and AND nodes denoting redundancy. Interconnections among the nodes denote their immediate functional dependencies. START supports hierarchical testing in accordance with the maintenance strategy; a failure source may be isolated to a component or a module at any level, e.g. LRU (line replaceable unit), SRU (shop replaceable unit), etc. Other practical features include options to integrate diagnosis with repair (after partial diagnosis) and to optimize test time, test cost, or test and repair cost. An interactive menu-mouse graphical interface serves as a high-level front end to these algorithms and enables the user to graphically enter and modify hierarchical functional models of systems