[LEAPSECS] Windows Server 2019

Stephen Colebourne scolebourne at joda.org
Wed Jul 18 23:14:12 EDT 2018

"In addition, there is no standard method for applying this frequency
adjustment, so that different implementations may disagree among
themselves in addition to the time error with respect to UTC."

As a IT professional, and author of date/time libraries, I cannot
stress enough how much a standard is needed here. We are going to have
both UTC (with leap seconds) and systems that smear ("UT-Smear") and
there is currently no agreed way to define the latter or move from one
to the other. I strongly suspect that Microsoft is going to have to
define a smear in order to meet old APIs, but this really should be
something well defined by a standard, not invented by a company.


On 18 July 2018 at 23:07, Steve Allen <sla at ucolick.org> wrote:
> as seen on slashdot and more, Windows Server 2019 will support leap seconds.
> https://blogs.technet.microsoft.com/networking/2018/07/18/top10-ws2019-hatime/
> That blog entry points at several MSword docs for admins and devs, and
> https://aka.ms/Dev-LeapSecond
> finishes with this interesting warning:
> Known issues:
> Some frameworks are known to calculate time incorrectly after a leap
> second occurs.  For example, the .NET Framework uses its own internal
> logic to determine what time it is.  Its logic does not account for
> leap seconds.  So after a leap second is introduced to the Operating
> System the output of "System.DateTime.Now.ToString()" will be ahead by
> one second of the local system time.  (We are working with the .NET
> framework team on this.)
> In combination with the many steps that it takes to configure Windows
> this sounds like there will be some really interesting results.
> --
> Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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