Toyota software bugs unlike those in flaky PCs

The electronic issues dogging the Toyota Prius signal that cars are increasingly susceptible to software bugs. Cars, however, are not PCs on wheels and have a different set of problems than that crash-prone computer on your desktop, according to an expert at Edmunds.com.

Anyone who has ever been in a Prius knows immediately that it's different, with its large LCD display on the dashboard, the computer-controlled buttons that switch the car into different fuel-efficiency modes, and the all-digital dashboard.

If the Prius is any indication of the future of cars, then cars with more computer-related glitches is part and parcel of this future. Highlighting this, earlier this month, Toyota issued a recall in the U.S. of approximately 133,000 2010 Prius (and 14,500 Lexus vehicles) to update software in the vehicle's antilock brake system (ABS) because of uneven braking.

"Cars have been getting more computer-controlled for years," according to Dan Edmunds, director of vehicle testing at car Web site Edmunds.com. "It's not just a recent development that's come with Prius. Take electronic throttles, I don't know of a car on the market today that doesn't have a drive-by-wire throttle system. That is very common," he said.

Edmunds continued. "Anti-lock brakes, electronic stability control. All of these are systems that have a computer that modifies something that the driver asks the car to do."

But a car packed with microprocessors does not exhibit the same kinds of problems that the freeze-prone PC on your desk does, according to Edmunds.

"The reason that people are so spooked right now is because everybody's desktop (PC) is prone to lockups and they ascribe the same sort of tendencies to cars," he said. "It makes it very easy to believe that some kind of software problem could wreak havoc on your car."

Car computer systems have different set of issues
Edmunds said that PCs are very different beasts than car-based computer systems. "The computer on your desk is designed to be all things to all people. It's designed to run Adobe Photoshop, Google Earth, and surf the Web--run all of these third-party software applications simultaneously. And then all of the different drives and video cards," Edmunds said. This hodgepodge of software and hardware that are mixed and matched across an infinite variety of configurations inevitably leads to instability, he said.

Not so in a car. "The computer running an ABS is more like a pocket calculator. It's designed to do one thing. It's not a buggy kind of device. It's more of a hardwired device that has one controlling program in it."

He continued. "In a car, one computer might control the ABS, one might control the engine. They are separate individual computers coded to do one job."

The weak link in a car isn't a virus or ill-behaved third-party app, but the computer code and how it responds, or fails to respond, to unforeseen conditions, said Edmunds. "The (computer's) performance is as good as the code. There is definitely opportunity for things to happen if the code doesn't cover all possible situations."

The Prius goes further with computer control than other cars because it needs to run everything in the car when the combustion engine is off. "In the case of the Prius, you have a more complicated car. The computer has to decide when the engine should be on, when the electric motors need to be on, when the regenerative braking needs to be on. So, definitely, there is a lot more going on with the engine control computer," he said.

The crux of the problem for cars like the Prius is unanticipated scenarios. "When you're developing a car, you're in a proving ground, a controlled environment. Out in the real world there are more random events you may not have predicted."

But even as deadly as a faulty electronic throttle control can potentially be--and that makes the bar much higher for car makers because the driver's life is at stake--a PC it's not, said Edmunds. A car's computer is not going to crash twice a week and not going to freeze on you every other day when you're pulling out of your driveway.

The next time your PC crashes, consider yourself lucky that the same flaky PC operating system is not controlling your car.