[ntp:questions] Re: simple time server
Richard B. Gilbert
rgilbert88 at comcast.net
Sun Aug 6 02:49:47 UTC 2006
Danny Mayer wrote:
> Darren Dunham wrote:
>>Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
>>>>By constrast, a Windows clock keeps local
>>>>time. If you transport a Windows computer from Los Angeles to New
>>>>York, you normally tell the kernel to change its clock by 3 hours. If
>>>>you transport a Unix system, you don't. You just tell the various
>>>>programs that report the kernel's time that you'd like to see it in
>>>Maybe YOU reset the Windows clock that way. Windows does have the
>>>facility to specify a time zone and at least some of us use that
>>>facility to set the correct time zone for the zone we happen to be in.
>>I believe "specify a time zone" and "tell the kernel to change its
>>clock" are equivalent on Windows. Yes?
> No. Windows uses UTC for internal timekeeping. Timezones are only for
> local display of time, just like Unix. Notice that you need to nothing
> to go between daylight savings time and local standard time in any
> timezone. VMS is the only operating system that I am aware of that uses
> local time for internal timekeeping, and that may have changed since I
> was involved with it. I don't know what IBM mainframes do.
VMS joined the modern era, timewise, back in the 1990's. I believe that
VMS V6.2-1 supported a UTC clock and local timezones. The UCX TCP/IP
stack (V4.0, I believe) supported a primitive (V3.x) ntpd. The time
change from standard to daylight and back is not automatic; you have to
run a script at 2:00 AM on D-day. If you're running a Database, you
shut it down while this is going on. Not sure if it's really necessary
but I've always been told to do it that way.
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