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← Most Expensive Bug in History - Software Debugging

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Showing Revision 6 created 05/24/2016 by Udacity Robot.

  1. You may have heard the story of Ariane 5 rocket which famously exploded on its first flight
  2. due to software bug sometimes called the most expensive software bug in history.
  3. Do you know why the Ariane 5 exploded?
  4. It exploded simply because it had a bug in a 64-bit integer to 16-bit integer conversion.
  5. The interesting thing though is that normally
  6. the code actually did have plenty of checks to track such illegal conversion.
  7. These checks were disabled in the Ariane 5 for reasons of performance.
  8. Picture what would have happened if the computer in the Ariane 5
  9. had been just so slightly be more performant to cover this particular check of a 64-bit
  10. to a 16-bit integer then the assertion would have triggered even during the launch,
  11. but the Ariane 5 actually does have a very good recovery mechanisms for failing assertions.
  12. It would have recovered, may be the flight could have done well
  13. and we would have escaped the most expensive software bug in history.
  14. $317,000,000 went into the sky because of a missing assertion.