Pioneering work on the reliability of electronic systems

Looking at software-reliablility differently

Generally speaking, quite a bit is already known about the lifetime behaviour of hardware. But it’s different with software. “There are no obvious causes for software defects, such as variations in the creative process, wear and tear, or physical stress from working conditions such as temperature, humidity or vibration. Software defects arise precisely from those things that are not directly visible or foreseeable. For example, a misinterpretation of the design specifications; mistakes when writing the code; inadequate or improper testing; memory leaks; or incorrect or unexpected use of the software. All defects that, in contrast to hardware, are not functions of usage. And that means you have to approach software reliability differently."

CQM quantifies error detection and debugging process and ties in with software development

"Even the best engineers, with the best knowledge and equipment, can’t prevent software defects. What you can do is conduct tests on the software designed to answer certain key questions. For example, how likely is it that there are serious errors in the software? And, going a little deeper, what is the likelihood of errors occurring while the software is being used within a given period by users with pre-specified user profiles? What matters most is that you can quantify these answers. And you have to include the uncertainty of the answers in the confidence intervals. From which the project manager can decide, on the basis of the predetermined reliability objective, whether the software is ready for release or requires more testing. Together with the Philips Lighting Reliability Manager, Willem van Driel, we’ve now developed a methodology for retrieving the data with which such questions can be answered. For this, we estimate software reliability growth models (SRGs) that describe the error detection and debugging process. This methodology is tied in with the software development process."

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_{Photo credits: CQM and Philips.}