RE: [LEAPSECS] two world clocks

From: Seeds, Glen <Glen.Seeds_at_Cognos.COM>
Date: Fri, 21 Jan 2005 09:57:16 -0500

> -----Original Message-----
> From: Leap Seconds Issues [mailto:LEAPSECS_at_ROM.USNO.NAVY.MIL]
> On Behalf Of Poul-Henning Kamp
> Sent: January 21, 2005 3:40 AM
> Subject: Re: [LEAPSECS] two world clocks
> >... What
> >reliable evidence do we have that programmers are screwing up UTC
> >left-and-right?
> Until two years ago Microsoft Windows got it wrong for Denmark.

I can believe they got the time zone wrong. That has nothing to do with
leap seconds, and would not have been solved by abolishing them.

> UNIX has a continuous timescale with no room for leap seconds
> which is supposed to be "UTC".
The POSIX clock is explicitly and deliberately not aligned with UTC or
any other absolute time standard. Facilities for converting the system
clock to local time are implementation-specific.

This was not an oversight. Considerable analysis went into understanding
how this would work. The bottom line is that it's not a problem for all
but a very few applications, which have ways to work around it. These
same applications have timekeeping synchronization costs that are far
larger than the costs of these workarounds.


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Received on Fri Jan 21 2005 - 06:57:42 PST

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