[LEAPSECS] [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

Martin Burnicki martin.burnicki at burnicki.net
Mon Jul 25 09:56:16 EDT 2016


Tony Finch wrote:
> Martin Burnicki <martin.burnicki at burnicki.net> wrote:
>>
>> IMO a better approach would be to let the system time run on TAI, and do
>> the conversion to UTC, and local time in the next step, by runtime
>> libraries.
> 
> The kernel needs to know UTC for things like filesystem timestamps.

I know. This is mainly to avoid ambiguities you'd have with time stamps
in local time, as under plain old DOS.

Using TAI for the file time stamps should be fine as well, it would even
avoid ambiguities for files which are written during a leap second. Of
course, if the kernel could *tell* the time stamps are TAI instead UTC
then tools like 'ls' could display the TAI timestamps in UTC, if required.

If you insist that file times should be UTC then the kernel could
convert the TAI time stamps to UTC before writing the file time stamps.

For example, ntpd already passes the TAI offset down to the kernel if it
knows this number, e.g. from a leap second file, or via autokey from an
NTP server.

Martin



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