COTS and Previously Developed Software
COTS/PDSSection 08: Software Certification (DO-178C)
Definition
Commercial Off-The-Shelf (COTS) software is software that was not developed with DO-178C compliance as a primary objective and is available commercially (e.g., operating systems, libraries, protocol stacks). Previously Developed Software (PDS) is software that was developed under DO-178C for a prior certification program and is being reused in a new application. Both categories present certification challenges. For COTS software, the full DO-178C lifecycle data is typically unavailable, so alternative means of compliance must be established — such as extensive testing, operational history credit (with caveats), or wrapping the COTS component with qualified interface protection. For PDS, change impact analysis and configuration management verification are required to ensure the software is applicable to the new installation.
Where This Shows Up
The use of COTS and PDS is economically attractive but certification planning must address the compliance gap. The certification authority expects that the safety objectives are met regardless of the software's origin. Options for COTS include: developing full DO-178C lifecycle data retrospectively (reverse engineering), testing the COTS software to a level commensurate with DO-178C objectives, or containing the COTS software within a robust partition and limiting its failure modes through architectural means. Each approach has trade-offs in cost, schedule, and risk.
Primary Sources
Addresses previously developed software and guidance for assessing its use in a new certification program.
FAA guidance on the use and certification of reusable software components.
Related Terms
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