Michael Barr has posted a critical assessment of NASA’s investigation into the unattended acceleration problem on Toyota vehicles. From the article:

These reports are very interesting in what they have to say about the quality of Toyota’s firmware and NASA’s review of the same. However, of greater significance is what they are not able to say about unintended acceleration. It appears that NASA did not follow a number of best practices for reviewing embedded software source code that might have identified useful evidence. In brief, NASA failed to find a firmware cause of unintended acceleration—but their review also fails to rule out firmware causes entirely.

The article goes on to detail “five recommended practices for firmware source code review” based on the author’s “experiences as both an embedded software developer and as an expert witness.”