[ntp:questions] Re: Windows timekeeping

David Woolley david at djwhome.demon.co.uk
Sat Aug 5 19:11:23 UTC 2006

In article <g_KdndAxRrxjUknZnZ2dnUVZ_tadnZ2d at comcast.com>,
Richard B. Gilbert <rgilbert88 at comcast.net> wrote:

> software part counts the ticks.  The system clock as I, and others, have 
> said keeps UTC unless some idiot has totally botched the configuration 
> of Windows (quite possible since the supply of idiots is inexhaustible).

Windows is a brand name that covers two completely different kernels.

Windows NT based kernels (including Windows 2000, 2003, 2005, and XP) use
UTC internally.  MS-DOS based kernels, including 3.0, 3.1, 95, 98, 98SE and
ME, use local time.  The NT kernels inherit from VMS, not from the
MS-DOS line.

I think the history is that MS-DOS was originally an OS for isolated,
non-portable, machines operated by unsophisticated users, so local time
was the easiest concept for the users to handle.  Unix was developed
by academics, so they were prepared to deal with more abstract concepts
and consider the long term.

Backwards compatibility prevented Microsoft making a change (although 
I seem to remember that Windows can be configured for a UTC RTC, but
this would probably confuse any new system administrator).

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