Date: Wed, 24 Mar 1999 07:50:02 -0800 (PST) From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/10609: adjtime bug (tv_sec >2147 ) and enhancement (nil first arg) Message-ID: <199903241550.HAA82892@freefall.freebsd.org>
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The following reply was made to PR kern/10609; it has been noted by GNATS. From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: haug@hawaii.conterra.com Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: kern/10609: adjtime bug (tv_sec >2147 ) and enhancement (nil first arg) Date: Wed, 24 Mar 1999 16:16:13 +0100 I don't really know if I think it makes sense to extend the area of adjtime(2)'s validity. If you were to tweak your clock 2148 seconds, it would take you 7160 minutes (at the 300msec/min fast rate). That is 5 days. Depending on you xtal, your clock may have drifted up to: 500PPM * 7160 * 60 = 214.8 seconds in the same amount of time, so we're talking about potentialy getting it 10% wrong... In comparison the ntp_adjtime() interface only allows you to tweak the phase +/- half a second. I really fail to see an application where it makes sense. If you are synchronizing via modem to ACTS or similar, you would be better off using NTPDv4 for that since it will try to discipline your xtals frequency error. Summary: I would rather return E2BIG if people try to do that, but I'm not religious about it. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." FreeBSD -- It will take a long time before progress goes too far! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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