NTP and POSIX Time in conflict?

[Alan Perry]

Did this discussion thread go anywhere?  I had a "poorly timed" disk crash and
lost a bunch of e-mail.

What operating systems use local time as their basic clock these days?  Just
wondering.

What was the issue with "NTP and POSIX Time in conflict?"

alan

>Some operating systems use local time as their basic clock. Novice
>programmers often tell me that this is a good thing. I always find it
>amusing to compare their arguments to the anti-leap-second arguments:
>
>   Clocks are local time            Clocks are non-leap-second counters
>   --------------------------------------------------------------------
>   Computer clocks are set by       Computer clocks are set by
>   humans, who use local time.      NTP, which counts non-leap seconds.
>
>   I don't know the time zone.      I don't know the UTC-TAI difference.
>
>   Who cares about occasional       Who cares about occasional
>   errors in time subtraction?      errors in time subtraction?
>
>   Governments change time zones.   IERS changes the leap-second table.
>   Keeping up to date is painful.   Keeping up to date is painful.
>
>   I just signed a contract that    I just signed a contract that
>   specifies a future local time.   specifies a future time in UTC.
>   How do I represent that time?    How do I represent that time?
>
>   An isolated system can't learn   An isolated system can't learn
>   about time-zone changes.         about new leap seconds.
>
>The unfortunate reality is that an isolated system can't maintain an
>accurate local-time clock. How do we react to this? Do we screw up the
>semantics of localtime(), saying that it's just fine for localtime() to
>ignore changes in time zones and in the leap-second table? Or do we
>maintain our standards for the semantics of localtime(), and acknowledge
>that isolated systems can't support it properly?
>
>---Dan
>
>
>