J. Cleland-Huang, A. Agrawal, M. Vierhauser, C. Mayr-Dorn: Breaking the Deep Freeze: Visualizing Change in Agile, Safety-Critical Systems, Journal IEEE Software, June 2020, Doi: 10.1109/MS.2020.3000104
Safety-critical software systems must be developed using rigorous safety assurance practices. This has led to the phenomenon referred to as the “big freeze” in which the cost, effort, and difficulty of introducing new functionality to an already certified product is prohibitively expensive. However, present day agile processes have greatly matured to the extent that organizations who have traditionally used waterfall approaches are actively experimenting with agile practices even across relatively high-criticality domains. At the same time, organizations experienced in agile development are increasingly building Cyber-Physical Systems (CPS), often without sufficient knowledge or instrumentation to adopt appropriate hazard analysis and safety assurance practices. The challenge in both scenarios is to manage, and more importantly understand change, and to further leverage automated software traceability to support the incremental development and maintenance of a safety case. This article explores solutions for visualizing and understanding change in highly-incremental, safety-critical development contexts.