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From: Jerry Cooperstein <coop@axian.com>
To: David Balazic <david.balazic@uni-mb.si>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Wrong clock initialization
Date: Wed, 21 May 2003 10:00:45 -0700	[thread overview]
Message-ID: <20030521170045.GA2130@p3.attbi.com> (raw)
In-Reply-To: <3ECA673F.7B3FB388@uni-mb.si>

This is not directly a kernel problem.  I developed this after
a glibc upgrade.  The problem is most distros (such as redhat)
make a symbolic link

   /etc/localtime -> /usr/share/zoneinfo/America/Los_Angeles

or whatever your timezone is.  On some of my systems, /usr/share is on
a disk partition that is not mounted at the time the link is needed
during initialization; the system then defaults to UTC.  As a result,
each time you boot up your system loses a time equal to the difference
between UTC and your local time zone.

To fix this, just make sure /etc/localtime is actually a file on the
root filesystem, not a link to a possibly unmounted filesystem.
Just copy the one pointed to by the link.

I have systems with the same partition/mount layout which have no
problem, so I don't know why some systems get confused.  So far I
have only seen this on laptops.

======================================================================
 Jerry Cooperstein,  Senior Consultant,  <coop@axian.com>
 Axian, Inc., Software Consulting and Training
 4800 SW Griffith Dr., Ste. 202,  Beaverton, OR  97005 USA
 http://www.axian.com/               
======================================================================



On Tue, May 20, 2003 at 07:34:55PM +0200, David Balazic wrote:
> Hi!
> 
> When the kernel is booted ( ia32 version at least ) , it reads
> the time from from the hardware CMOS clock , _assumes_ it is in
> UTC and set the system time to it.
> 
> As almost nobody runs their clock in UTC, this means that the system
> is running on wrong time until some userspace tool corrects it.
> 
> This can lead to situtation when time goes backwards :
> 
> timezone is 2hours east of UTC.
> UTC time : 20:00
> local time : 22:00
> 
> System time between boot and userspace fix : 22:00UTC
> System time after fix : 20:00UTC
> 
> Comments ?
> 
> 
> -- 
> David Balazic
> --------------
> "Be excellent to each other." - Bill S. Preston, Esq., & "Ted" Theodore
> Logan
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      parent reply	other threads:[~2003-05-21 16:47 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-05-20 17:34 Wrong clock initialization David Balazic
2003-05-20 18:08 ` David D. Hagood
2003-05-20 18:10 ` george anzinger
2003-05-20 18:27   ` David Balazic
2003-05-20 20:21     ` george anzinger
2003-05-20 18:17 ` Michael Buesch
2003-05-20 18:26   ` David Balazic
2003-05-20 20:16 ` Jan Harkes
2003-05-21 11:38 ` Jesse Pollard
2003-05-21 17:00 ` Jerry Cooperstein [this message]

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