Requirement Engineering Embedded versus IT: If you analyses the book market, publications or conferences on requirements management and Requirement Engineering, you will find that more than 90% consider requirements engineering from the point of view of IT software systems. There are very few publications that look at the topic from the perspective of embedded systems. On the one hand, it is the great success of some pioneers in IT development that procedures for the RE have been discussed and established in the last 20 years. On the other hand, it leads to problems in the development of embedded systems, because these procedures are adopted without consideration. Read more
Requirement Engineering theory: In most of the requirement engineering publications, the focus is on management aspects. The collection and management of requirements is discussed extensively. In the following blog I discuss important aspects which are not sufficiently considered in the RE theory. I start with the definition of Requirement Engineering in the book “Requirements Engineering Fundamentals” (Klaus Pohl, Chris Rupp). Read more
In the first part of the blog I defined the term Implicit Testing and discussed root causes for the need of implicit tests. Now, in the second part I will focus on the disadvantages of such tests and on possible solution approaches with the goal to avoid these disadvantages. Read more
In larger safety-critical projects, quite often I hear the following statement: “Well, the Requirement A is indirectly or implicitly proven with the test XY!” Do you know this sentence as well? Have you ever experienced what can happen in late project phases when you have tested many requirements indirectly?
The blog defines the term in part 1 and it discusses the causes of implicit testing. Read more
The book “User Stories” from Mike Cohn (ISBN 978-0321205681) has inspired me to think about the relationship between user stories and requirements. In software development, agile methods are often preferred in recent years. The classic approaches, especially the waterfall model and the V-model, seem to be more and more outdated.
As a result, user stories are preferred more and more. Do user stories really help to deliver better software quality? Read more
Specification Architecture Requirement : For an increasing number of systems in the industrial automation functional safety requirements must be fulfilled. The IEC 61508 compliance must be demonstrated for the software development.
On the other hand, there are commercial requirements which often severely limit the product development budget.
The solution lies in an efficient development process that meets the safety-relevant requirements. A prerequisite for a successful implementation of such a process is a deep understanding of the standard and a clear definition of used terms. In the following blog, I discuss the three terms Specification Architecture Requirement. Read more
In my daily projects in the automotive and industrial automation industry I’m continually confronted with the following question: How many levels of software requirements have to be written? That’s an interesting question, especially if we take the aerospace industry also into account. Software requirement level are a key topic if you want to improve your requirement engineering process. Therefore, I want to highlight in this blog post this topic a bit closer. I will compare the specifications of functional safety standards IEC 61508, ISO 26262 and DO-178B / C. In the final conclusion I will provide project best practices based on my more than 15 years of experience.
In my view, a good software specification is divided into two major parts: architecture / design and textual requirements.
The architecture describes, most predominantly in graphical form, the structure and design of the software. In particular, the data and control flows are shown. The focus of textual requirements is on the description of the functionality, and the time demands on the system.
The initial question of this blog refers to the number of levels of textual requirements. Not included is the level of system requirements, which must always be present. Read more