Re: F-22 Raptor software problem

Simon Wright <simon.j.wright@xxxxxxx> writes:
"peter koch" <peter.koch.larsen@xxxxxxxxx> writes:
On Feb 28, 8:44 am, Keith Thompson <k...@xxxxxxx> wrote:
I'm only guessing, but I doubt that the error was caused by using
local time. My suspicion is that the error occurred not when
crossing the International Date Line (which is crooked, as you can
see on a map), but when crossing the 180th meridian, when the
longitude jumped from 179.909 to -179.990.

Yes - that makes far more sense. I had a very difficult time (!)
believe that the problem had anything to do with timezones.

I could believe it if there were requirements to do something say
every quarter-hour on the quarter-hour in local time. What seems hard
to imagine in a military aircraft is the 'local time' part!

It would be easier to do something every quarter-hour in UTC; it will
be done at the sames, even in places with half-hour time zones. And
an F-22 at top speed can cross a time zone in a few minutes.
Performing tasks that depend on local time wouldn't make much sense;
performing such tasks in a critical subsystem (which is what crashed)
makes even less sense.

--
Keith Thompson (The_Other_Keith) kst-u@xxxxxxx <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
.

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