DO-178B, Software Considerations in Airborne Systems and Equipment Certification, is a standard published by RTCA, Inc that the FAA accepts for certifying software in avionics.
Understand is used by quite a number of people developing to this standard. We don’t have a specific DO-178B “solution”, but the tool helps in quite a few parts:
- The HTML reports generated by Understand can act as “as built” Software Detailed Design (SDD) documents.
- Additional SDD information such as globals used and globals cross reference can be accessed via the _globals_used.pl and _globals_xref.pl scripts that ship with Understand in the SciTools\scripts\perl folder. More details on the Perl API and how to run scripts are available here.
- Certain coding standards, such as “no interrupt handler can be in the call chain of another interrupt handler” can be implemented as Understand scripts, permitting automatic re-checking as the code changes.
- If requirements are embedded in source as comments, Understand scripts can do requirements tracing and impact assessments. Using this capability you readily track changes in requirements as to where they affect code, and vice versa.
- When doing DO-178B mandated code reviews, Understand is very useful. It isn’t a requirement for doing DO-178B code reviews, but it makes code reviews more useful, efficient and accurate – the main intention of the standard.
So Understand can satisfy some portions of the standard, help you be better at doing other parts, and also is a generally useful tool to the practice engineer to minimize mistakes and understand what they are doing in the code.