What does the exchange of requirements with ReqIF have to do with systems engineering?
I have already mentioned ReqIF several times, which Requirements Interchange Format. But I haven't even explained what that actually is. Readers of the English-language Formal Mind Blogs should be familiar with ReqIF, but here is a brief introduction in German. I would also like to answer the question of what ReqIF actually has to do with systems engineering.
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What is the problem that ReqIF solves?
ReqIF is an exchange format for requirements. The problem is quickly described: When a manufacturer submits requirements to a supplier, in which format should this be done? The "classic" formats are Word, Excel or PDF. All three have the problem that the requirements are relatively unstructured and only machine-readable to a limited extent. If it were only about the text, that would be one thing; but normally requirements are attributed, e.g. with a status or a priority. It becomes even more problematic when the supplier has to respond, either with comments or perhaps even a specification.
And now let's look at the automotive industry, where tens of thousands of requirements in a specification are not uncommon. So it's no wonder that ReqIF comes from this industry. ReqIF enables the loss-free, machine-readable exchange of requirements: Hierarchically, with all attributes and links.
ReqIF is widely used
In the meantime, every tool in requirements management that wants to be taken seriously supports the standard. With the tool ReqIF Studio there is also a free editor that can be used to quickly inspect and validate ReqIF files. ReqIF Studio is based on the Eclipse RMF project, which is the open-source reference implementation of ReqIF. Lightweight requirements management is also possible with it.
In the meantime, all "big" tools such as DOORS®, Polarion® and Integrity® support, and there are numerous new tools that process ReqIF-based data.
ReqIF and Systems Engineering
Back to the question of what all this has to do with systems engineering. First of all, requirements management is an important discipline of systems engineering. Traceability to requirements is needed in many areas, from verification and validation (V&V) to project management.
Not least in the direction of Industry 4.0, much depends on how well the industry masters requirements management for the new systems. (ReqIF - Standard for the manufacturing industry)
Few companies have one tool that covers all aspects of systems engineering, but instead use a heterogeneous tool chain. ReqIF is a future-proof standard that enables a stable exchange of requirements between tools. Of course, this requires adapters to be available or purchased for the relevant tools. But by using an open and well-documented standard, the risk of problems is low.
OSLC as an alternative
There are of course alternatives for the integration of tools for sharing requirements. Noteworthy here is OSLC (Open Services for Lifecycle Collaboration). This is also an open standard for web services (i.e. machine-readable web services). The idea is that data (such as requirements) can be retrieved via a corresponding OSLC server.
OSLC and ReqIF are actually mutually exclusive and therefore represent two different approaches to the integration of requirements. Both have their raison d'être. OSLC tends to be more suitable for large organizations that have a well-managed IT landscape. This is because OSLC requires servers with appropriate rights and everything that goes with them.
ReqIF enables file-based work and is therefore extremely well suited for the exchange of requirements across company boundaries, which is what it was originally designed for. However, it can also be used for lightweight, file-based requirements management. The ReqIF files can be easily managed in a file repository such as Subversion or git.
Conclusion
Even if it was originally "only" designed for requirements management, ReqIF is also ideally suited as a bridge to systems engineering. There are numerous solutions, from open source to highly integrated proprietary. Thanks to open standards, the user has a wide range of solutions to choose from.
Disclaimer: Michael Jastram is Managing Director of Formal Mind GmbH and co-developed ReqIF Studio.
Hello Mr. Jastram,
A good article that explains the first basics well. You have correctly described the differences and application scenarios.
I would go one step further and emphasize that a ReqIF file is always a snapshot, a specific baseline of (mostly but not exclusively) textual requirements.
What might be somewhat misleading is the statement about the OSLC server. OSLC is intended to provide tools with an OSLC interface just like ReqIF support (see Doors).
It would be very interesting for me to consider whether all specified ReqIF fields can be mapped without extending the OSLC requirements specification and vice versa. In other words, as a user, am I able to save requirements in a proprietary data model in a tool and then use them as required in the development process via OSLC or ReqIF?
Best regards,
Christian Muggeo
Thanks for the constructive comments. That's right - ReqIF is designed as a snapshot. However, there are now some tools that also use it as a data model (ReqIF Server, fmStudio, ReqEdit...). But this is more of a „twisting“ of the standard and the intended use case.
I'll take the suggestion regarding OSLC on board and will carry out and post a systematic comparison of the ReqIF data model and OSLC requirements management.
Hello Michael,
Oslc only describes the access and basic (minimum) methods. In principle, ReqIF can be generated from an RE tool using OSLC and, conversely, data from a ReqIF file can be saved to the tool using OSLC. However, this depends on the methods offered by the tool. The only limitation of DOORS Next that we know of so far is, for example, that there is probably no access function to the hierarchy of a module. We are currently investigating this in more detail as we are designing an OSLC ReqIF adapter.
Best regards
Nikolai
Hello Nikolai,
This is also my understanding that all features of a single SpecObject can actually be mapped for individual requirements, but a systematic check would certainly be interesting. If there are any interesting results from your investigation, I would be very interested to hear them.
Greetings, - Michael