[SystemSafety] A software assurance question

[SPRIGGS, John J]

Someone told me recently that modern civil avionics is implemented as a virtual architecture over common processing modules, rather than the individual boxes I used to design in the last millennium.  This raises a software assurance question:
The guidance used when getting civil avionics software certificated for use (current versions RTCA/DO
178C & EUROCAE Document ED
12C) was originally prepared on the basis of identifying an internally-consistent and valid set of assurance evidence for the software in question running on a particular piece of hardware.  In a virtual architecture, processes can, in principle, move around in response to specified events, and so they are not necessarily running in the same environment as that in which they were tested and 'assured'.  An underlying assumption of the guidance is therefore no longer valid.

So, is DO-178/ED-12 guidance used for such architectures?  If so, how do you argue that it is fit for this modified purpose?


John Spriggs 
Head of System Integrity
NATS

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