Architectural approaches to limiting the criticality of commercial-off-the-shelf (or other re-used software) components in avionics systems

There are several known architectural techniques available with at least the potential to ameliorate some of the hazards associated with the use of lower assurance level commercial-off-the-shelf (COTS) or previously-developed-software (PDS) components in avionics system requiring overall assurance at a higher level. But using these techniques, either singly or in combination, is not likely to be quite as simple as extreme optimists might like it to be - under some circumstances, it might not even be cost-effective at all. But given the requisite meticulous and extensive engineering analysis of the factors discussed in this paper (and probably numerous others as well), the techniques discussed here can be considered as at least potentially part of the avionics software engineering armamentarium