Comparing software design for testability to hardware DFT and BIST

Abstract

Software is replacing hardware whenever possible, and this trend is increasing. Software faults are every bit as pervasive and difficult to deal with as hardware faults. Debugging software faults is manual, time consuming, often elusive and since they affect all systems deployed, most often they are critical. Design for Debugging would ensure that a software package can be readily debugged for any software fault. A comprehensive software test, however, is intended to eliminate the need for ad hoc debugging and ideally all “bugs” (we call software faults) would be caught and identified by the software test. Thus, it is imperative that the software community adopt means to ensure that software components are designed in a way that will detect and isolate software faults. This requirement is familiar to designers of hardware systems. Could the discipline of hardware design for testability (DFT) and Built-In [Self] Test (BIST) apply to software design for testability? The purpose of this paper is to discuss how many of the testability requirements and techniques for hardware DFT can be applied to software.