From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 19 Jul 2005 16:18:41 +0100 (BST) Received: from lug-owl.de ([IPv6:::ffff:195.71.106.12]:35038 "EHLO lug-owl.de") by linux-mips.org with ESMTP id ; Tue, 19 Jul 2005 16:18:23 +0100 Received: by lug-owl.de (Postfix, from userid 1001) id A1B67F0075; Tue, 19 Jul 2005 17:20:08 +0200 (CEST) Date: Tue, 19 Jul 2005 17:20:08 +0200 From: Jan-Benedict Glaw To: linux-mips@linux-mips.org Subject: Re: Updating RTC with date command Message-ID: <20050719152008.GG20065@lug-owl.de> Mail-Followup-To: linux-mips@linux-mips.org References: <20050719143110.GD3108@linux-mips.org> <20050719144230.GE20065@lug-owl.de> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="m972NQjnE83KvVa/" Content-Disposition: inline In-Reply-To: X-Operating-System: Linux mail 2.6.11.10lug-owl X-gpg-fingerprint: 250D 3BCF 7127 0D8C A444 A961 1DBD 5E75 8399 E1BB X-gpg-key: wwwkeys.de.pgp.net X-Echelon-Enable: howto poison arsenous mail psychological biological nuclear warfare test the bombastical terror of flooding the spy listeners explosion sex drugs and rock'n'roll X-TKUeV: howto poison arsenous mail psychological biological nuclear warfare test the bombastical terror of flooding the spy listeners explosion sex drugs and rock'n'roll User-Agent: Mutt/1.5.9i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 8554 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: jbglaw@lug-owl.de Precedence: bulk X-list: linux-mips --m972NQjnE83KvVa/ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, 2005-07-19 16:06:21 +0100, Maciej W. Rozycki = wrote: > On Tue, 19 Jul 2005, Jan-Benedict Glaw wrote: >=20 > > hwclock is the userspace utility to manually once set the time. In > > normal operation, this should only be called _once_, after the system is > > switched on for the very first time. >=20 > Well, `hwclock' should normally be used to update the RTC every time=20 > after a manual system clock update. Which of course should only be done once. Ever :) > > During lifetime, ntpd should execute and thus the system's current time > > will be written to the HW clock every now and then. Additionally, most >=20 > Note that ntpd only updates minutes and seconds and then only if the=20 > difference is small -- to account for the existence of time zones and a= =20 > system-specific relation between the time recoreded by the system and one= =20 > handled by the RTC. Also the feature is broken by design -- ntpd=20 > shouldn't do that at all in principle and in practice it leads to the=20 > system time being corrupted on some machines using an RTC interrupt for= =20 > the system timer tick. Aren't we expected to keep UTC time inside the HW clock? So there's no problem with timezones. Also, if your timer interrupt source it that broken that ntpd cannot track it, then you're having more servere problems... > > distributions seem to also update the HW clock at system shutdown time. >=20 > Which is where it should really happen. I disagree. IFF there's a known good time, it's acceptable to write it into a backing HW clock. In case there isn't (any longer), it's probably better to not write to the HW clock at all. Probably it's contents is better than a wrongly manually adjusted local date setting... I do trust ntpd, but do I trust someone who looks at it's watch? > > So the correct solution to your problem is to either shutdown once > > (workaround) or keep ntpd running (the solution[tm]). >=20 > I think you've got the figures reversed (well, it's useful to have ntpd= =20 > running, but it should not fiddle with the RTC). Well, I stated my oppinion. Maybe ntpd shouldn't set the clock (or make the kernel set it internally), but for sure I don't want the HW clock being set by hand (except very first power-up of the system) and by no means if local time came up from a manual process. MfG, JBG --=20 Jan-Benedict Glaw jbglaw@lug-owl.de . +49-172-7608481 = _ O _ "Eine Freie Meinung in einem Freien Kopf | Gegen Zensur | Gegen Krieg = _ _ O fuer einen Freien Staat voll Freier Buerger" | im Internet! | im Irak! = O O O ret =3D do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA)= ); --m972NQjnE83KvVa/ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFC3RooHb1edYOZ4bsRArUpAJ0WbflH/Vn45E4CRaiaIwD6gDy9KgCfaq5V xd2zhvQVYbp842YFF4jhY3Q= =sbhH -----END PGP SIGNATURE----- --m972NQjnE83KvVa/--