A Look Back at the Audi 5000 and Unintended Acceleration

I was in high school in the late 1980’s when NHTSA (pronounced “nit-suh”), Transport Canada, and others studied complaints of unintended acceleration in Audi 5000 vehicles. Looking back on the Audi issues, and in light of my own recent role as an expert investigating complaints of unintended acceleration in Toyota vehicles, there appears to be a fundamental contradiction between […]

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An Update on Toyota and Unintended Acceleration

In early 2011, I wrote a couple of blog posts (here and here) as well as a later article (here) describing my initial thoughts on skimming NASA’s official report on its analysis of Toyota’s electronic throttle control system. Half a year later, I was contacted and retained by attorneys for numerous parties involved in suing Toyota for personal injuries and […]

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Introducing Barr Group

In the ten months since forming Barr Group, I have received many questions about the new company. As we enter the new year, I thought it a good time to use this blog post to answer the most frequently asked questions, such as: What does Barr Group do? Who are Barr Group’s clients? How is Barr […]

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Building Reliable and Secure Embedded Systems

In this era of 140 characters or less, it has been well and concisely stated that, “RELIABILITY concerns ACCIDENTAL errors causing failures, whereas SECURITY concerns INTENTIONAL errors causing failures.” In this column I expand on this statement, especially as regards the design of embedded systems and their place in our network-connected and safety-concious modern world. […]

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Embedded Software Training in a Box

I am beaming with pride. I think we have finally achieved the holy grail of firmware training: Embedded Software Training in a Box. Priced at just $599, the kit includes Everything-You-Need-to-Know-to-Develop-Quality-Reliable-Firmware-in-C, including software for real-time safety-critical systems such as medical devices. In many ways, this product is the culmination of about the last fifteen years of […]

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What NHTSA/NASA Didn’t Consider re: Toyota’s Firmware

In a blog post yesterday (Unintended Acceleration and Other Embedded Software Bugs), I wrote extensively on the report from NASA’s technical team regarding their analysis of the embedded software in Toyota’s ETCS-i system. My overall point was that it is hard to judge the quality of their analysis (and thereby the overall conclusion that the […]

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Firmware-Specific Bug #10: Jitter

Some real-time systems demand not only that a set of deadlines be always met but also that additional timing constraints be observed in the process. Such as managing jitter. An example of jitter is shown in Figure 1. Here a variable amount of work (blue boxes) must be completed before every 10 ms deadline. As […]

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What Belongs in a C .h Header File?

What sorts of things should you (or should you not) put in a C language .h header file? When should you create a header file? And why? When I talk to embedded C programmers about hardware interfacing in C or Netrino’s Embedded C Coding Standard, I often come to see that they lack basic skills and information about […]

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Rate Monotonic Analysis and Round Robin Scheduling

Rate Monotonic Analysis (RMA) is a way of proving a priori via mathematics (rather than post-implementation via testing) that a set of tasks and interrupt service routines (ISRs) will always meet their deadlines–even under worst-case timing.  In this blog, I address the issue of what to do if two or more tasks or ISRs have equal priority and whether […]

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Is Reliable Multithreaded Software Possible?

Until earlier this month, I’d overlooked a most interesting May 2006 article in Embedded Software Design magazine by Mark Bereit titled “Escape the Software Development Paradigm Trap“. The article opines that the methods we use to design embedded software, particularly multitasked software with interrupt service routines and/or real-time operating systems, are fundamentally incompatible with reliability. Here’s the critical analogy: […]

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