Do we need standards for product line engineering - and if so, how many?

This guest article by Dr. Danilo Beuche deals with the topic of product line engineering, another complexity driver in systems engineering. Some readers may be surprised to learn that there is not just one, but several standards on this topic. Dr. Beuche explains below whether this makes sense.

The English version of this article is in the pure-systems blog to read.

Guest article by Danilo Beuche

Full disclosure: Both myself and other pure-systems team members have been and/or are involved in international standardization bodies such as AUTOSAR, OASIS and ISO. I also represent pure-systems in the INCOSE Product Line Working Group. So this will not be a contribution from an objective observer, but rather from a man who has spent some of his life helping to get standards written and applied in practice.

As a result of a standardization activity launched a few years ago as an initiative by members of the Product Line Engineering Working Group of the INCOSE was launched, a new standard for Product Line Engineering (PLE) was published by ISO a few days ago: the ISO26580:2021 (Software and Systems Engineering - Methods and Tools for the Feature-Based Approach to Software and Systems Product Line Engineering). This was the trigger for my contribution, as I would like to share some facts and my views on standards in PLE with you.

The standard describes the industry best practice for PLE, the feature-based approach. It gives us names for concepts around this approach and puts them into context (i.e., it creates an ontology). It also describes the requirements for the elements used to implement this approach. You can use this standard to judge whether an engineering approach is a feature-based PLE approach or not (and what is missing if not). If you have ever thought about the question "What is a feature?", you will find an answer there. That's a good thing. However, the ISO 26580 standard mentioned above is not the first standard on PLE and will not be the last to be published. One question comes to mind:

Why are multiple standards needed for PLE and how many standards do we need?

Dr. Danilo Beuche

Before we dive deeper into this question, let's look at what already exists: Even ISO already has several standards on PLE in the ISO 2655x/2656x family of standards, with the ISO 26550 as the basis for all these standards (including ISO 26580 as a specialization of the concepts in ISO 26550ff).

Further standards

But there is more: since #AUTOSAR 4, this standard provides meta-model elements to represent concepts of architectural variability in the automotive software domain, including a fully defined Metamodel for feature modeling through to XML data representation. This is clearly a standard intended to define data models for tool-based collaboration. It does not define how you would use the concepts to execute PLE. And it is focused on one thing: the automotive software architecture and implementation domain.

Further standards with embedded aspects of product line engineering are currently being developed, such as OMG's SysML V2 and the OASIS Variability Exchange Language (VEL), both of which address the challenge of representing machine-readable information related to variability (which is a core concept of PLE) in a standardized way. The scope of SysML V2 is model-based systems engineering, while VEL is a language for exchanging variability information between the PLE Factory Configurator (which, by the way, is a term defined by ISO26580 and refers to tools such as pure-systems' pure::variants and Biglever Gears) and authoring tools for shared superset assets (such as requirements management tools or MBSE tools) will serve.

In contrast to the ISO standards for PLE, all the other standards mentioned above focus on providing concrete means for data exchange and data processing, but lack the methodological aspect that is present in the ISO standards.

Dr. Danilo Beuche

All of these standards actually have their place in the big picture. Let's look at the automotive industry. It develops future cars and related infrastructures (e.g. smart highways) using model-based systems engineering, which it then uses as input for AUTOSAR-based software development. Variability is linked to these different models/data domains and needs to be controlled holistically, using VEL as a lingua franca to exchange variability information between different tools, such as a SysML V2 modeling tool, AUTOSAR tooling and the PLE factory configurator tool. The ISO standards help us to set up a methodology and understand what requirements the tools and the organization need to meet.

With this in mind, it is clear that we need to harmonize the various standards in such a way that collaboration is possible without this being an obstacle to evolution and innovation. However, there will not be one standard that applies to all.

Conclusion

I think the PLE community is on the right track as many of us are involved in the various standardization activities. We are putting a lot of effort into communicating with the domain experts for systems engineering, tool vendors, etc. They need to understand the importance of having aligned concepts that are open for collaboration.

If we see Product Line Engineering as a truly holistic approach (which it is), we must also include mechanical engineering and its standards (especially those in the area of digital representation such as ISO 10303). Therefore, it is likely that we will see more standards or further developments of existing standards appearing in relation to PLE.

About the author

Prof. Dr. Danilo Beuche is co-founder and CEO of pure-system and one of the leading minds in Product Line Engineering (PLE). Danilo is driven by the idea of helping companies to develop better and more durable products, always keeping economic reuse and sustainability in mind. In 2001, he co-founded pure-systems, a software company specializing in services and tool development for the application of product line technologies in embedded software systems. As a market leader in PLE, pure-systems helps global corporations and mid-sized companies to keep costs down while improving the quality and safety of their products.

Before founding pure-systems, Danilo worked at the University of Magdeburg on tool support for feature-based software development. Since 2016, he has also been an honorary professor at the Institute for Information Systems (IWI) at Leipzig University.

Photo by Nathan Dumlao on Unsplash