My Life

Required downtime as part of uptime

“The recent shutdown of LAX due to an FAA radio outage was apparently caused by a Windows 2000 integration flaw, possibility related to an old Windows 95 bug. An article at the LA Times claims that the outage was caused by human error, as the system will automatically shut down after 49.7 days (related to this Windows 95 flaw?), and a technician didn’t reboot the system monthly as he should have. This happened after an upgrade from Unix to Windows. I don’t think blame should be assigned to the technician who missed the task; rather, it seems a gross oversight for the FAA to guarantee that such a critical system will crash after only one missed maintenance task. Who’s really at fault?”

And we trust this system to keep our pllanes in the air? Umm, I don’t think I want to fly home for christmas anymore!

Note that the FAA insists that they’re currently implementing a better solution than “reboot every month”. Better hurry, guys, you’ve only got 47.3 days left. — lol

The problem here is the software made by Harris does not handle a rollover of the GetTickCount() function turning back to 0. This function counts the number of milliseconds since the OS was last booted so it should be obvious to anybody that the returned unsigned 4 byte integer cannot go on forever.

So the badly written Harris software has this bug and their solution (which was really not that bad of a work around) was to manually reboot the system every 30 days, but as a fail-safe, they had a scheduled task to do a reboot on the 49th day just in case. The 49th day came because of procedural error.

Umm, the real question, regardless of who’s fault it is…. Is WHY was this system implemented in the first place?!

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