[tz] The zoneinfo file system tree structure ?

Brian Inglis Brian.Inglis at systematicsw.ab.ca
Fri Feb 13 20:46:06 UTC 2015

On 2015-02-13 12:54, Steve Allen wrote:
> On Thu 2015-02-12T16:56:55 -0500, J William Piggott hath writ:
>>         There  are  two  separate  databases  in the zoneinfo system, posix and
>>         'right'. 'Right' (now named leaps) includes leap seconds and posix does
>>         not.
>>               To  use  the  'right'  database  the System Clock must be kept in
>>         UTC + leap_seconds, i.e., TAI - 10.
> I would clarify that to read
> 		To use the 'right' database the System Clock must
> 	  count allseconds of UTC (and TAI), including leap seconds.
> 	  From the beginning of 1972 onward this is equivalent to
> 	  setting the System Clock to (TAI - 10 s).
>>                                              This allows calculating  the  exact
>>         number of seconds between two dates that cross a leap second epoch.
> I would clarify that to read
> 					      This means that the difference
> 	between two dates that span a leap second counts the number of
> 	seconds of TAI (and this is not congruent with POSIX).
>>                                                                             The
>>         System Clock is then converted to the  correct  civil  time,  including
>>         UTC,  by  using the 'right' timezone files which subtract the leap sec-
>>         onds. Note: this configuration is considered experimental and is  known
>>         to have issues.

Do astronomers or physicists keep their system clocks on TAI and use these right/leaps files?

Take care. Thanks, Brian Inglis

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