[ntp:questions] Odd offset for PPS DCD w/ Garmin GPS 18x LVC

Dave Hart davehart at gmail.com
Wed Mar 23 04:00:22 UTC 2011

On Wed, Mar 23, 2011 at 1:32 AM, lellis <larry.ellis at gmail.com> wrote:
> Thanks to all.  I am using Garmin 3.20, as it it turns out.
> However, I reverted to 4.2.5p233 of Dave Hart's builds, and it does
> not appear to have the same strange behavior.  I had been using
> 4.2.7p138 (which I first installed only yesterday).

Thats quite a leap back.  4.2.5 and 4.2.7 are ntp-dev (odd-numbered
minor version) and are essentially daily snapshots of the latest
source rolled up on days when that source has changed, or as soon
afterwards as practical.  These are by their nature more likely to
regress while having the latest and hopefully greatest code.  The
number following p increases with each ntp-dev snapshot tarball.  Some
p releases have a lot of changes relative to the prior, some have only
a typo in ChangeLog fixed.

4.2.4 and 4.2.6 are the most recent two examples of ntp-stable, which
represents an attempt to provide a slower-moving target with extended
maintenance in the form of (many less) point releases such as the
current 4.2.6p3.  To that end, there are prereleases named along the
lines of 4.2.6p3-rc1, and a few times so far (and maybe yet in the
future) like 4.2.6p3-beta1.  The prereleases of 4.2.6p3 are based on
4.2.6p2 and preceded 4.2.6p3.

All changes to ntp-stable are simultaneously merged into ntp-dev, so
the ntp-dev ChangeLog file describing the changes with each release
contains information on all releases so far, including the latest
ntp-stable.  Referring to that file to date 4.2.5p233 compared to

scroll to ChangeLog and click the first column link to browse the latest rev

(4.2.5p233-RC) 2009/10/15 Released by Harlan Stenn <stenn at ntp.org>
(4.2.7p138) 2011/03/08 Released by Harlan Stenn <stenn at ntp.org>

So 4.2.5p233-RC was during the release candidate cycle for 4.2.6, that
is, we were attempting to stabilize then-current ntp-dev into a
credible 4.2.6 stable release to succeed the 4.2.4 releases.

> I'll try a few of Dave's other builds to see if I can see where the
> boundary is.  I don't know how he numbers his builds so I don't know
> whether this build is thought to be stable or not.  It was only built
> a few weeks ago.

Everything in http://davehart.net/ntp/win/x86/ aside from a few of the
first builds in April 2009 is intended to be a straightforward compile
of the corresponding .tar.gz source tarball after it has been released
(though I don't actually start from the tarball, I start from a
checkout of the source tagged with the tarball version number).  I
make a point of not mixing my development activities with the building
of Windows binaries for distribution -- which I really should
automate.  These binaries should be practically identical to anyone
else's who builds from the same source version using the same Visual
C++ 2008 [fr]EE compiler against the same OpenSSL library version (I
used 0.9.8j or 0.9.8k IIRC until 4.2.7p131 when I switched to openssl
1.0.0c).  Terje Mathisen and Meinberg also distribute binaries for
Windows, the latter with a very nice installer which I rely upon, but
a sadly outdated version of ntpd which is deployed probably thousands
of times a month.  My first substantial changes were integrated in
4.2.5p162, 9 April 2009, and I've been pretty active since then.  I
typically install once on each target machine using the Meinberg
installer creating a dedicated ntp account, then immediately overlay
more recent *-bin.zip executables from
http://davehart.net/ntp/win/x86.  I recommend overriding the default
install path (\Program Files\NTP) to simply \ntp or similar, as
Windows Vista and Windows 7 perform magic on \Program Files for
non-elevated (admin) users which can be very confusing, as changes
under \Program Files (vista) or \Programs (win7) by non-elevated users
are silently redirected to per-user shadow directories invisible to
other users.  In other words, you edit ntp.conf and restart ntpd and
it doesn't see your changes, if you forgot to make them from an
elevated administrator command prompt.

The order you see .zip files is not easily customized -- it's
alphabetical, which mixes up the chronology a little bit, as far
example 4.2.7p138 precedes 4.2.7p14 in the list.

There will be no more 4.2.5 releases.  There may be more 4.2.6
releases (next would presumably be 4.2.6p4-rc1) but nothing is under
way right now.  I would focus your testing on 4.2.6p3 (as the basis
for any future 4.2.6 releases) or recent 4.2.7, simply because those
are the active development heads.  Hopefully you won't have to reach
back more than a month or three to bisect the change in behavior, if
you follow that route.

Thanks for your interest and support,
Dave Hart

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