From: "M. Warner Losh" <imp@bsdimp.com>
To: pavel@suse.cz
Cc: linasvepstas@gmail.com, david@lang.hm, goodgerster@gmail.com,
kyle@moffetthome.net, slashdot@jameshallam.info,
davidn@davidnewall.com, linux-kernel@vger.kernel.org,
hancockr@shaw.ca, ntpwg@lists.ntp.isc.org,
pretzalz@techhouse.org, burdell@iruntheinter.net,
nick@nick-andrew.net, jeff@kosowsky.org
Subject: Re: [ntpwg] Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009
Date: Mon, 12 Jan 2009 10:07:12 -0700 (MST) [thread overview]
Message-ID: <20090112.100712.107765266.imp@bsdimp.com> (raw)
In-Reply-To: <20090112161115.GA1474@ucw.cz>
In message: <20090112161115.GA1474@ucw.cz>
Pavel Machek <pavel@suse.cz> writes:
: On Mon 2009-01-05 11:42:35, Linas Vepstas wrote:
: > 2009/1/5 <david@lang.hm>:
: > > On Mon, 5 Jan 2009, Linas Vepstas wrote:
: > >
: > >>> Arguably the kernel's responsibility should be to keep track of the
: > >>> most fundamental representation of time possible for a machine (that's
: > >>> probably TAI) and it is a userspace responsibility to map from that
: > >>> value to other time standards including UTC,
: > >>
: > >> Yes, this really does seem like the right solution.
: > >>
: > >>> using control files
: > >>> which are updated as leap seconds are declared.
: > >>
: > >> Lets be clear on what "control files" means. This does
: > >> *NOT* mean some config file shipped by some distro
: > >> for some package. That would be a horrid solution.
: > >> People don't install updates, patches, etc. Distros
: > >> ship them late, or never, if the distro is old enough.
: > >>
: > >> A more appropriate solution would be to have
: > >> either the kernel or ntpd track the leap seconds
: > >> automatically. First, the ntp protocol already provides
: > >> the needed notification of a leap second to anyone
: > >> who cares about it (i.e. there is no point in getting a
: > >> Linux distro involved in this -- a distribution mechanism
: > >> already exists, and works *better* than having a distro
: > >> do it).
: > >
: > > I disagree with this. NTP will only know about leap seconds if it was
: > > running and connected to a server that advertised the leap seconds during
: > > that month.
: > >
: > > for example, if you installed a new server today, how would it ever know
: > > that there was a leap second a couple of days ago?
: >
: > OK, good point. Unless your distro was less
: > than a few days old (unlikely), you are faced with the
: > same problem. Sure, eventually, the distro will publish
: > an update (which will add to the existing list of 36 leap
: > seconds -- which is needed in any case, since no one
: > has a server that's been up since 1958), but this is
: > unlikely to happen during this install window.
: >
: > The long term solution would be write an RFC to extend
: > NTP to also provide TAI information -- e.g. to add a
: > message that indicates the current leap-second offset
: > between UTC and TAI.
:
: Offset is not enough; you'd have to provide list of all previous leap
: seconds with 'when it happened' timestamps.
Well, today you can ftp the leapseconds.txt file from NIST. Of
course, that assumes your machine is on the network, and not a dumb
slave of a smart head-end that's off the net...
Warner
next prev parent reply other threads:[~2009-01-12 17:08 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-02 19:25 Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009 Linas Vepstas
2009-01-02 20:04 ` Diego Calleja
2009-01-02 20:25 ` Robert Hancock
2009-01-03 6:32 ` David Newall
2009-01-03 6:37 ` Ben Goodger
2009-01-04 8:43 ` David Newall
2009-01-04 9:00 ` Kyle Moffett
2009-01-04 10:03 ` David Newall
2009-01-04 11:13 ` david
2009-01-04 23:15 ` David Newall
2009-01-04 23:25 ` Chris Adams
2009-01-05 0:01 ` David Newall
2009-01-05 0:41 ` Alan Cox
2009-01-05 8:43 ` David Newall
2009-01-05 19:47 ` Alan Cox
2009-01-05 0:29 ` david
2009-01-04 23:37 ` David Newall
2009-01-05 1:05 ` david
2009-01-05 0:14 ` David Newall
2009-01-05 0:21 ` Ben Goodger
2009-01-05 6:34 ` David Newall
2009-01-05 23:03 ` Linas Vepstas
2009-01-05 0:44 ` Alan Cox
2009-01-05 5:48 ` Linas Vepstas
2009-01-05 14:33 ` Nick Andrew
2009-01-05 16:08 ` Linas Vepstas
2009-01-05 17:51 ` david
2009-01-05 17:42 ` Linas Vepstas
2009-01-06 2:27 ` john stultz-lkml
2009-01-06 4:53 ` Linas Vepstas
2009-01-06 5:00 ` Linas Vepstas
2009-01-06 19:40 ` [ntpwg] " M. Warner Losh
2009-01-06 19:50 ` M. Warner Losh
2009-01-07 3:50 ` Danny Mayer
2009-01-07 4:52 ` Linas Vepstas
2009-01-07 10:03 ` David Newall
2009-01-07 17:24 ` M. Warner Losh
2009-01-08 16:51 ` Magnus Danielson
2009-01-07 14:34 ` Danny Mayer
2009-01-07 15:42 ` Linas Vepstas
2009-01-07 19:23 ` Danny Mayer
2009-01-07 16:04 ` john stultz
2009-01-07 17:36 ` M. Warner Losh
2009-01-07 17:39 ` M. Warner Losh
2009-01-07 19:31 ` Alan Cox
2009-01-07 19:42 ` M. Warner Losh
2009-01-08 3:57 ` Danny Mayer
2009-01-08 4:42 ` M. Warner Losh
2009-01-08 10:48 ` Alan Cox
2009-01-08 10:56 ` Alan Cox
2009-01-08 22:22 ` David Mills
2009-01-08 15:02 ` M. Warner Losh
2009-01-08 18:57 ` Marshall Eubanks
2009-01-08 20:09 ` Steve Allen
2009-01-12 16:11 ` Pavel Machek
2009-01-12 17:07 ` M. Warner Losh [this message]
2009-01-12 21:45 ` [ntpwg] " Valdis.Kletnieks
2009-01-06 2:31 ` Nick Andrew
2009-01-06 1:59 ` David Newall
2009-01-06 2:18 ` Chris Adams
2009-01-06 2:51 ` Nick Andrew
2009-01-06 9:40 ` Alan Cox
2009-01-07 1:17 ` Nick Andrew
2009-01-07 9:37 ` Alan Cox
2009-01-07 9:46 ` David Newall
2009-01-07 9:54 ` Alan Cox
2009-01-07 10:18 ` David Newall
2009-01-07 10:52 ` Alan Cox
2009-01-07 13:45 ` David Newall
2009-01-07 14:10 ` Alan Cox
2009-01-07 14:36 ` David Newall
2009-01-07 15:40 ` Alan Cox
2009-01-10 9:46 ` David Newall
2009-01-07 22:13 ` Chris Adams
2009-01-07 13:33 ` Chris Adams
2009-01-07 13:37 ` Alan Cox
2009-01-07 14:12 ` David Newall
2009-01-07 14:09 ` David Newall
2009-01-07 21:42 ` Chris Adams
2009-01-04 11:35 ` Valdis.Kletnieks
2009-01-05 0:08 ` David Newall
2009-01-06 3:53 ` Valdis.Kletnieks
2009-01-04 17:20 ` Kyle Moffett
2009-01-03 7:00 ` Chris Adams
2009-01-04 8:41 ` David Newall
2009-01-02 20:29 ` Linas Vepstas
[not found] ` <8752a8760901021328t545a0327v58faebe1e921680a@mail.gmail.com>
2009-01-02 21:29 ` Ben Goodger
2009-01-03 0:21 ` Chris Adams
2009-01-03 2:23 ` Duane Griffin
2009-01-03 3:45 ` Linas Vepstas
2009-01-03 4:41 ` [PATCH] " Chris Adams
2009-01-03 4:52 ` Duane Griffin
2009-01-03 18:01 ` [PATCH] v2 " Chris Adams
2009-01-03 19:04 ` Duane Griffin
2009-01-03 20:01 ` Linas Vepstas
2009-06-08 2:18 ` Ben Hutchings
2009-06-18 22:34 ` Chris Friesen
2009-06-18 22:58 ` Ben Hutchings
2009-06-18 23:48 ` Chris Friesen
2009-01-06 2:21 ` john stultz-lkml
2009-01-06 2:25 ` Chris Adams
2009-01-06 4:35 ` Linas Vepstas
2009-01-03 3:49 ` Linas Vepstas
2009-01-03 4:02 ` Ben Goodger
2009-01-03 4:46 ` Duane Griffin
2009-01-03 4:50 ` Ben Goodger
2009-01-03 22:58 ` Jeffrey J. Kosowsky
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