Clock : can't handle winter/summer time automatically ?

Adam Conrad adconrad at
Tue Mar 28 10:15:20 UTC 2006

Peter Garrett wrote:
> Vincent Trouilliez <vincent.trouilliez at> wrote:
>> Or is there something special I should do to enable automatic time
>> changes ? I didn't see any obvious setting in the clock preferences in
>> any case :-/

What's the output of 'grep UTC /etc/default/rcS' on your system?  If
your hardware clock it in UTC time (UTC=yes), then everything will
magically work, no matter how long your computer is off, since the
system clock will always just be hardware(UTC) +/- the TZ offset.

If your hardware clock is in local time (UTC=no), then we assume on boot
that your hardware clock is correct and set the system clock from that
(though ntpdate, if it's installed, should violently fix that for you
later in the boot process)

Anecdote time: When I did more work in Windows development, I had a
machine that triple-booted Win95, WinNT4 Workstation, and WinNT4 Server.
 After the DST switch, the machine ended up jumping 3 hours, as I
rebooted into each OS, and it was convinced that I needed my clock adjusted.

Given that the only reason to EVER use "UTC=no" (or, rather, to have
your hardware clock set to local time) is because you're dual-booting
with Windows, which doesn't know how to deal with UTC clocks, we tend to
assume that the adjustment's probably already been done for you in your
other OS.

> It should do it, of course - I noticed on Breezy that the time adjustment
> was broken too. Yesterday's libc6 updates appear to fix the problem (can't
> speak for Dapper as I'm not running it yet)

Your problem, of course, was specific to Australia's changing their
daylight savings bracket to accommodate the Commonwealth Games.  I don't
think Vincent (who appears to live in France) was suffering from the
same bug. :)

... Adam

More information about the ubuntu-users mailing list