There are four essential measures in the development of safety-critical systems. Design of safe systems Measures to minimize random hardware errors Measures to minimize systematic hardware and software errors Organizational measures (management of functional safety) Particularly in the design of safe systems, the principle of Freedom of interference is a powerful measure. What’s this? The […]
The proof of a 100% structural source code coverage is required by almost all functional safety standards (IEC61508, ISO26262, DO 178C, etc.). In the individual SIL / ASIL levels, only the type of source code coverage is differentiated. Essentially, the Statement Coverage (low SIL / ASIL Level), the Branch Coverage and the MC / DC […]
IEC 61508, ISO26262, DO 178C, ISO 25119: Have you ever encountered these abbreviations in your professional life? If so, there is a high probability that you are already implementing functional safety projects in your company or that you are entering the market in the near future. Perhaps you have already made the experience, or at […]
In the first part of the blog I defined the term „Implicit Testing“ and discussed root causes for the need of implicit tests. 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.
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 […]
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 The classic approaches, especially the waterfall model and the V-model, seem to be more and more outdated.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 […]
For an increasing number of systems in the industrial automation functional safety requirements must be fulfilled. The IEC61508 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. […]
In the first part (Link) I explained the basic idea, which is behind the tool qualification. I have already given an overview of the four most frequently used measures. In this article, I will discuss each of these 4 measures in more detail and name the respective advantages and disadvantages.
Many companies and project teams that carry out projects for the first time in the field of functional safety have the impression that the topic of tool qualification is critical to success and involves a great deal of effort. Although this issue is, of course, important and also involves a certain cost effort, the subject […]
If a project getting difficulties with writing requirements, there is Test Driven Development (TDD) often referred to as the solution. Is that really the solution? If so, why TDD has not really become widely accepted in the software development up to now? In this blog I will express my thoughts about this topic.