[ntp:questions] Fwd: The Earth's not slowing down fast enough to suit Motorola...
brad.knowles at skynet.be
Fri Oct 10 20:05:08 UTC 2003
Thought you might appreciate the humour in this one:
>From: bmanning at karoshi.com
>Subject: The Earth's not slowing down fast enough to suit Motorola...
>To: nanog at merit.edu
>Date: Fri, 10 Oct 2003 11:15:19 -0700 (PDT)
>> Date: Tue, 07 Oct 2003 23:33:45 -0700
>> Subject: The Earth's not slowing down fast enough to suit Motorola
>> Motorola reports that several GPS receivers in its Oncore line will
>> misdisplay the date on 28 Nov 2003 at midnight UTC. For a one-second window
>> the receivers will mistakenly report the date as 29 Nov instead of 28 Nov.
>> Here's why. Every couple of years or so for the past three decades, the
>> International Earth Rotation Service has announced a leap-second because the
>> Earth is rotating slightly more slowly than an 86400-second day would
>> suggest. But since 1 Jan 1999, we've had an unusually long dry spell
>> without any leap seconds. The GPS week number in the UTC correction
>> parameter is 8 bits long, which allows for 256 weeks of unambiguous time
>> calculation. Until now this parameter has never rolled over, but because of
>> the dry spell 28 Nov will be exactly 256 weeks after the most recent leap
>> second, and the rollover will contribute to the bug.
>> Steve Allen writes in <http://www.ucolick.org/~sla/leapsecs/onlinebib.html>
>> that some JDAM smart bombs and other munitions are rumored to contain these
>> receivers. Anyone intending to use those weapons around the magic window
>> might want to reschedule their bombing runs for some other time. ...
> for all you NTP/GPS junkies out there... :)
Brad Knowles, <brad.knowles at skynet.be>
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
-Benjamin Franklin, Historical Review of Pennsylvania.
GCS/IT d+(-) s:+(++)>: a C++(+++)$ UMBSHI++++$ P+>++ L+ !E-(---) W+++(--) N+
!w--- O- M++ V PS++(+++) PE- Y+(++) PGP>+++ t+(+++) 5++(+++) X++(+++) R+(+++)
tv+(+++) b+(++++) DI+(++++) D+(++) G+(++++) e++>++++ h--- r---(+++)* z(+++)
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