Agile methods for open source safety‐critical software

Abstract

The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the right amount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion.

Scrum in Practice: an Overview of Scrum Adaptations

“…While most cases discussed smaller IT companies, some large corporations were also represented, such as PayPal [5], Ericsson [19], and Intel [12]. Other studies focused on rather specialized areas or industries, such as the cruise line industry [1] or healthcare [16]. In terms of geographical dispersions, most studies focus on Western Europe, the Nordic regions, and the United States.…”

“…Context method guidance [24] procedures, artifacts, roles [16] [14] Recently, some authors began to describe cases of the introduction of Scrum to non-traditional contexts. For example, Könnölä et al (2016) report on successful adoption of Scrum to embedded system development [24].…”

Suitability of Agile Methods for Safety-Critical Systems Development: A Survey of Literature

“…Gary [13] warranted. This reinforces Boehm [14] argument comprehensive project management is required for safety-critical software development.…”

Towards applying a safety analysis and verification method based on STPA to agile software development

“…However, both of them suggest an up-front design, which is contrary to the nature of Scrum [8]. Gary et al [12] mentioned design for safety in agile methods in their paper, but no safety analysis technology is explored.…”