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New Jaguar XJ Suffers Blue Screen of Death

Posted by CmdrTaco on from the i-meant-to-do-that dept.

An anonymous reader writes "CNET UK is reporting that it crashed a £90,000 Jaguar XJ Super Sport — one of the most technologically advanced cars on the planet today. It's not the sort of crash you'd imagine, however — An unforseen glitch somewhere within the car's dozens of separate onboard computers, hundreds of millions of lines of code, or its internal vehicular network, led to the dramatic BSOD, which had to be resolved with the use of a web-connected laptop."

1 of 301 comments (clear)

  1. Insufficient paranoia by Animats · · Score: 5, Interesting

    Many years ago, I was at Ford Aerospace, where we had some slight involvement with the Ford EEC IV engine control module. The designers of that were paranoid about a failure of the module making the car immobile. So they did the following:

    • The device was designed for a 30 year life span. (Many 1980s Fords are still running with EEC IV modules, so they did it.)
    • The program for the device was etched into the silicon of the CPU. There is no way to change it without replacing the entire module. Huge amounts of effort were put into getting this small program right, including some proof of correctness work. It was successful; there's never been a recall.
    • There is a removable module with a ROM that has engine parameters. (The format is known; people have made their own for racing purposes.) It's just tables, no code. It's a bulky metal-cased plug-in module, hard to damage.
    • The device starts from a clean ground state at power-up. There is no persistent state that can prevent startup.
    • There's a dumb backup mode in the program. If the complex engine control algorithm fails, it reverts to a simple backup mode. Performance isn't very good.
    • There's a second hardware backup mode in the ignition controller. This was referred to internally as "limp-home mode". If a timer in the ignition controller detects that the EEC isn't responding, it drops into a mode where the spark fires each time a pulse from the crankshaft position sensor comes in. In this mode, there's no spark advance, no smart fuel injection, no active emissions control, no engine/transmission coordination, and top speed is about 25MPH. You can still drive the car.

    Designers today are not being sufficiently paranoid. They're assuming that the entire system stays up and that tow trucks are easily available.