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Property:Leap-Second
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Term
Term: | Leap-Second | Wiki | Freetz | IPPF | whmf | AVM | Web |
Short for: | Leap Second | ||||||
Location: | Lexicon >> Internationalisation | ||||||
Weblinks: | Wikipedia.int - Wikipedia.de | ||||||
Description: | Occasional 1-second correction of the UTC |
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Details
A Leap-Second is a positive or negative 1-second correction of the UTC to keep the time in sync with the earth rotation.
A solar day
is one rotation of the earth, which is drifting and which is not as precise as our need for accuracy of time.
The speed of the rotation of the earth is not stable and it is slowly decreasing.
To keep an UTC day in sync with a mean solar day
the UTC specification permits to insert or remove a second when it's
required. This is permitted at the end of each month, but all corrections so far happened on Jun 30
or Dec 31
.
A negative Leap-Second removes the time 23:59:59
from the end of the respective month:
23:59:57 -> 23:59:58 -> 0:00:00
A positive Leap-Second adds the time 23:59:60
to the end of the respective month:
23:59:59 -> 23:59:60 -> 0:00:00
Since a Leap-Second is applied to the UTC it happens simultaneously worldwide, regardless of any Timezone.
So far (2022-08) 27 Leap-Seconds were applied since 1972, all of which were positive.
FRITZ!OS
Since fw 4.63 FRITZ!OS uses chronyd to synchronize the system time via NTP, which supports Leap-Seconds.
Since the chrony.conf used does not contain a leapsecmode
directive the default mode system
is used.
This means that the system time will be tweaked by the Kernel as explained above, doing a "hard" switch.