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The benefits of modified condition/decision coverage (MC/DC) in development of safety critical software are well recognized. Use of commercial-off-the-shelf (COTS) software is encouraged, and vendors of COTS software have expressed interest in developing a standard interface to assist in carrying out functions needed for the safety critical domain. A useful analogy can be drawn between a complex integrated circuit, with millions more storage locations and logic gates inside than pins on its interface, and an executable version of software, with many more variables and logical statements inside than are directly visible on its interface description. IEEE has developed an interface standard for testing package integrated circuits (that is, the tests are conducted through the interface pins), called boundary-scan. An analogous interface specification for software modules has been proposed in a COTS software forum, initially by Therese Smith and continued by Dr. Gregory Eakman of Pathfinder Solutions, who has completed scholarly work in this area. The FAA is advancing the technology used to support interface metadata. Net-centric architecture increases both the visibility of the metadata repository and the level of automation used to interact with the metadata. Given that the software vendors are pursuing a strategy for testability, there is interest at FAA in whether the testability is useful, and if so, in expanding the metadata to be maintained in a proposed "FAA interface management system" to include interface data used for testing.