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Toyota Hardware Defects/software Bugs


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Long synonymous with the word "quality," Toyota Motor Corporation has been taking a beating due to the serial recall of many of its most popular models, from the Camry to the Prius. The company has described itself as growing too fast and been accused of being arrogant in its apparent dismissal of safety complaints and customer concerns.

During months of increasingly bad publicity, Toyota has steadfastly maintained that such failures—sudden acceleration and inadequate braking—were the result of purely mechanical faults, not its software. However, this defense has been disputed by a number of outside analysts and engineers, seeing in Toyota a harbinger of a worrisome future when microprocessors replace mechanical control systems in all machines.

Steve Wozniak, co-founder of Apple, publicly insisted that Toyota's problems go way beyond defective gas pedals. As reported by CNET, he announced at the Discovery Forum 2010 "Toyota has this accelerator problem we've all heard about. Well, I have many models of Prius that got recalled, but I have a new model that didn't get recalled. This new model has an accelerator that goes wild, but only under certain conditions of cruise control. And I can repeat it over and over and over again—safely. This is software. It's not a bad accelerator pedal. It's very scary, but luckily for me, I can hit the brakes." 

Toyota maintains out-of-control acceleration is purely a hardware problem. John Hanson, the company's national manager of environmental safety and quality communications, was quoted in the same CNET story, "After many years of exhaustive testing, we have not found any evidence of an electronic [software] problem that would have led to unwanted acceleration."

So… hardware or software? Perhaps a combination of both. The challenge is that complex systems like automotive electronics are difficult to test thoroughly or verify mathematically.

As early as August 2009, the San Jose Mercury News was covering this issue. According to the expose/article/investigation, "The National Highway Traffic Safety Administration disclosed that Volvo was recalling late-model S80s, XC70s, and XC60s because of a stalling problem linked to a software bug. The year before that, software-related stalls led to the recall of 2006 Chrysler Jeep Commanders. In 2004, Mitsubishi recalled Outlanders due to an electronic control module that could overheat and start fires. And in 2002, Volkswagen recalled Beetles, Jettas, and Golfs because the brakes' electronic controls could short-circuit and cause fires."

Ron Wilson, executive editor of Electronics Design, Strategy, News, a trade newspaper for the electronics industry, said, "… so now, after decades invested in metrics-driven verification, formal verification, and methodology management, we find that our chips don't work as expected because the software is still being 'verified' by feeding it test cases until the schedule expires. And we find that our cars run into things for the same reason, and the press, of course, will blame the problem on 'electronics.'" 

Consumers may never know the true cause of Toyota's serial troubles. However, I can predict as complex systems become increasingly microprocessor-dependent, software failures caused by design flaws or coding errors will be as commonplace as bugs in our personal-computer software. That’s reassuring…


Alan Zeichick (zeichick@acm.org), a technology analyst in the San Francisco Bay Area, blogs at ztrek.blogspot.com.

 

 


 

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