The role of extensibility in software standards for automatic test systems

The extension of standardized software interfaces provides a consistent format by which software vendors expose unique functional features of a product, as well as features common with other products, but not supported by existing standards. Extensibility is critical in the field of automatic test systems (ATSs) due to the diversity of existing hardware and software and the need to maintain systems over long periods of time. The paper describes the principle of interface extensibility and shows that, when properly used, extensions do not compromise the interoperability benefits obtained through standardization. Modern software interfacing technologies provide effective support for extensibility. The paper illustrates this support by analyzing the extensibility features of various ATS software standards. This analysis is used to derive a set of rules for designing interface extensions. Extensibility in the emerging automatic test markup language (ATML) standards is presented in detail and illustrated through examples