Date: Wed, 6 Sep 2000 03:40:06 -0500 From: David McNett <nugget@slacker.com> To: Paul Herman <pherman@frenchfries.net> Cc: cjclark@alum.mit.edu, John Turner <john@drexeltech.com>, freebsd-questions@FreeBSD.ORG Subject: Re: How to force GMT/UTC Message-ID: <20000906034006.B62094@dazed.slacker.com> In-Reply-To: <Pine.BSF.4.21.0009060951340.274-100000@bagabeedaboo.security.at12.de>; from pherman@frenchfries.net on Wed, Sep 06, 2000 at 10:00:33AM %2B0200 References: <20000905234426.D69158@149.211.6.64.reflexcom.com> <Pine.BSF.4.21.0009060951340.274-100000@bagabeedaboo.security.at12.de>
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On 06-Sep-2000, Paul Herman wrote: > (Sarcasm aside :) it matters to me. Is there any chance of FreeBSD > reflecting this? In /usr/src/share/zoneinfo/etcetera there seems to > be 0.00 difference between GMT and UTC in both -STABLE and -CURRENT. > > I'm no zoneinfo expert, but I'm willing to work on a patch. Anyone > know off hand where some good detailed docs are on the difference > between GMT/UTC? http://tycho.usno.navy.mil/systime.html will overwhelm you with the gory details of time measurement and, specifically, the differences between GMT and UTC. The Reader's Digest condensed answer is that UTC recognizes leap seconds and GMT does not. The two (GMT and UTC) are guaranteed to never differ by more than 0.9 seconds. Perhaps the more signifigant issue is that NTP, the protocol we all (presumably) use to keep our clocks synchronized is UTC-based. If you're relying on netdate, or ntpd, or xntpd or any equivalent method to keep your system clock synchronized, then you are UTC-synced, and not GMT. There's no way to encode the differential beteen UTC and GMT in a zoneinfo file, as near as I can tell, since the differential is variable. -- ________________________________________________________________________ |David McNett |To ensure privacy and data integrity this message has| |nugget@slacker.com|been encrypted using dual rounds of ROT-13 encryption| |Birmingham, AL USA|Please encrypt all important correspondence with PGP!| To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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