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Bug#504590: (forw) Bug#504590: clock-setup: OpenSolaris uses local time by default


Christian Perrier forwarded me the question, as a longtime Solaris and
OpenSolaris user, so let me try to shed more light on this.

The executive summary is, yes, by default, on *x86* systems, both
Solaris and OpenSolaris considers the system clock to be the local time.

The longer explanation:
This is a very old convention, that probably dates back from when Sun
acquired Interactive Unix for i386/i486 systems, to merge it into
Solaris and make it Solaris x86.
The manual dates back at least from Solaris 2.4 in 1994:

I'm not sure how the Debian installer works on SPARC, and if it allows
multiboot there, but this feature is x86 only. Solaris SPARC, and most
probably the upcoming OpenSolaris SPARC use UTC, as shown in rtc(1M):

     On x86 systems, the rtc command reconciles the difference in
     the  way  that  time  is established between UNIX and MS-DOS
     systems. UNIX systems utilize  Greenwich  Mean  Time  (GMT),
     while MS-DOS systems utilize local time.

The rtc command is run in the crontab at 02:01 every day. It's a no-op
on SPARC. On x86, when it's the day for changing the time, it adjusts
the system time accordingly so it stays on local time, and keeps track
there of the time difference between system time and UTC.

Thus in CET, I have:

And in CEST, it's:

Yes, as has been pointed out, it's definitely an issue if the system
isn't up when the time changes. It will only be updated on the next time
the command is run, which can take a while depending on the conditions
the system is run.

Also, the system can be set to UTC manually, but it's not very common
practice, even on Sun x86 hardware.

FWIW, there's an open bug about this, but I don't think it'll go
anywhere fast:

And yes, it's clunky, and has been the cause of at least one bad issue:

I wouldn't point a finger at anybody for the blame. When it was
introduced, MS-DOS compatibility was important. It still is, and both
the PC hardware manufacturers and the leading operating system vendor
consider the BIOS time is the local time. Probably the real error was by
IBM of not putting an RTC in its first PC, then defaulting it to local
in the XT or AT. But who would have guessed?

However, MS-DOS wasn't changing the time by itself, whereas nowadays,
every OS does it automatically, which is a problem with several systems
installed, and one of them is inheriting from MS-DOS.


> ----- Forwarded message from Colin Watson <cjwatson@ubuntu.com> -----
> Subject: Bug#504590: clock-setup: OpenSolaris uses local time by default
> Reply-To: Colin Watson <cjwatson@ubuntu.com>, 504590@bugs.debian.org
> Date: Wed, 5 Nov 2008 12:26:56 +0000
> From: Colin Watson <cjwatson@ubuntu.com>
> To: submit@bugs.debian.org
> X-Mailing-List: <debian-boot@lists.debian.org> archive/latest/135870
> X-CRM114-Status: Good  ( pR: 43.0249 )
> Package: clock-setup
> Version: 0.97
> Severity: normal
> Tags: patch
> User: ubuntu-devel@lists.ubuntu.com
> Usertags: origin-ubuntu ubuntu-patch jaunty
> Apparently OpenSolaris uses local time by default rather than UTC. This
> was reported as
> https://bugs.launchpad.net/ubuntu/+source/clock-setup/+bug/279065, and,
> while I found this surprising (as noted in the comments on that bug),
> the configuration file quoted there contains a comment that seems to be
> adequate evidence. I suggest the attached patch; comments?

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