Saturday, May 2, 2015

It must be a Seattle thing...

It must be a Seattle thing...  I'm sure most of my readers are intimately familiar with that most annoying CTL-ALT-DEL fix for anything that goes wrong with Windows.  “Did you reboot?” is the first question any help desk will ask when you report a Windows problem.  Microsoft is, of course, based near Seattle.

Today comes the news that Boeing is advising all owners of 787 Dreamliners to “reboot” their aircraft at least once every 248 days – power it down and back up.  I don't think they have a CTL-ALT-DEL function on those planes ... but it sounds like maybe they need one!  Oh, and Boeing is also based near Seattle.


For the geeks: the problem was traced to a 32-bit integer overflow.  There's a counter that tracks 1/100ths of a second since power up, and 2^31 1/100ths of a second is ... ta da! ... about 248 days.

One wonders whether the programmer was simply ignorant about integer overflow (unfortunately, a common issue) or whether they simply didn't think it was possible an aircraft could be powered up that long.  Boeing noted that this hasn't actually occurred to any aircraft – they caught it in testing...

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