Quality First. Measuring a Safety-Critical Embedded Software Development Process.

摘要

Software which is embedded in aircraft to which people entrust their lives becomes safety-critical and consequently must be of the highest quality. Failures of such software must be virtually non-existent. Due to the high costs of aircraft, hypothetical software failures would also incur major financial losses. To guarantee that the safety of aircraft is an uncompromisable requirement, an independent government agency certifies aircraft as fit-for-use. The experience with a software development process model accommodating both safety-critical requirements as well as commercial requirements is described. The findings are based on process and product metrics. The first two versions of the software product have successfully passed the certification and are currently being flown in numerous aircraft. In fact the software product is so successful that it will be adapted to other aircraft models. Measuring the requirements evolution contributed to the change from a waterfall based software development process to a spiral software development process. Design stability is reflected in the module evolution but needs to be complemented by other information. Requirements evolution and its implementation status combined with design stability help in the trade-off between additional deliveries, their functions and their release dates.