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From: Rob Seaman sea...@noao.edu
Sent: Sunday, October 24, 2010 4:53 PM
To: Leap Second Discussion List leapsecs@leapsecond.com
Subject: Re: [LEAPSECS] Cost: getting rid of GMT discontinuing leap
seconds
(snipped in fulfillment of Abrahamic
In message fb47749d-5340-44e5-95ea-0bcd6496a...@noao.edu, Rob Seaman writes:
Poul-Henning Kamp wrote:
Why did astronomers use UTC as timescale in their systems, where UT1 should
have been used?
Astronomers use both UTC and the general notion of UT. Sometimes
they use UT1. We use numerous
On 25 Oct 2010, at 02:19, Warner Losh wrote:
NASA already uses GMT when they really mean UTC.
Microsoft use GMT when they mean clock on the wall time in countries whose
winter timezone is GMT or UTC, including daylight savings which is even more
pernicious. Hence calendar appointments say
Warner Losh wrote:
UTC is the only game in town. It is the legal time everywhere, for
all practical purposes[*].
Do you really consider it reasonable to change the definition to which the
law refers? When complying with the law proves too cumbersome, shouldn't
legislators consider a change in
On Oct 25, 2010, at 12:01 AM, Brian Garrett wrote:
More accurately, civil timekeeping is sorta kinda like mean solar time. For
now.
See numerous (perhaps beyond count) threads from the archives.
One more time. The entire reason that the ITU-R scheme can be contemplated is
that the SI
--
From: Rob Seaman sea...@noao.edu
Sent: Monday, October 25, 2010 7:53 AM
To: Leap Second Discussion List leapsecs@leapsecond.com
Subject: Re: [LEAPSECS] Cost: getting rid of GMT discontinuing leap
seconds
On Oct 25, 2010, at 12:01 AM, Brian
Nero Imhard n...@pipe.nl wrote:
leap seconds being a vast improvement over rubber seconds
That is your opinion (and apparently that of the other technocrats), but
I totally disagree. I want mean solar time, but I want it to be a real
number with all the standard mathematical properties of a
Here is a cost that has not yet been mentioned. Many sources still refer
to the basis of civil time (before adjustment for time zone and daylight
saving) as Greenwich Mean Time. This can still be justified because
although the meridian for which UTC is the mean solar time moves over
the
: ashtongj ashto...@comcast.net
Sender: leapsecs-boun...@leapsecond.com
Date: Sun, 24 Oct 2010 12:08:03
To: leapsecs@leapsecond.com
Reply-To: ash...@ieee.org,
Leap Second Discussion List leapsecs@leapsecond.com
Subject: [LEAPSECS] Cost: getting rid of GMT discontinuing leap seconds
Here
In message 1275094941-1287937815-cardhu_decombobulator_blackberry.rim.net-1452
3531...@bda950.bisx.prod.on.blackberry, p...@2038bug.com writes:
Examples of such programs with a material manifestation of a problem?
The CASIMO Flight Control software is a typical example: Every time
a leap second
On 24 Oct 2010 at 18:12, Poul-Henning Kamp wrote:
Medicine production is another case: In continuous production
setups, all materials have to be traceable to with second granualirity
Why is the precise second something was manufactured or shipped so
urgent? As a consumer, the only
On Oct 24, 2010, at 4:35 PM, Daniel R. Tobias wrote:
On 24 Oct 2010 at 18:12, Poul-Henning Kamp wrote:
Medicine production is another case: In continuous production
setups, all materials have to be traceable to with second
granualirity
Why is the precise second something was
Medicine production is another case: In continuous production
setups, all materials have to be traceable to with second granualirity
(FDA, EU and other regulations), which basically means that either
nothing happens over the leap second (ie: maintenance shutdown) or
everything in the factory
I asked:
What coherent system design process led the engineers to select UTC in spite
of the existence of leap seconds?
Warner Losh asserted:
UTC is the only game in town.
The foundation of civil time is universal time, that is - mean solar time. UTC
is a widely available realization of
Poul-Henning Kamp wrote:
Why did astronomers use UTC as timescale in their systems, where UT1 should
have been used?
Astronomers since time immemorial have used mean solar time. GMT, a standard
international zero-point, was codified in 1884 (Steve will correct me).
Universal Time (UT) is
Another place where seconds are important is the stock market. I
don't know the details. Obviously it doesn't matter what time scale
they use as long as everybody uses the same one. (and the legal
paperwork says it's OK)
According to my friends who work for various Wall Street firms, UTC
No such examples exist yet. However, once the difference between UT1
and UTC becomes great enough to matter in daily affairs, a person
who would benefit by interpreting a timestamp applied by some
computer, where said timestamp contains GMT, can argue that it
MUST mean UT1, and can't possibly
At 7:30 PM -0600 10/24/10, Warner Losh wrote:
I asked:
What coherent system design process led the engineers to select
UTC in spite of the existence of leap seconds?
Warner Losh asserted:
UTC is the only game in town.
The foundation of civil time is universal time, that is - mean
Can you point to one that's broadcast, in real time, around the planet
like UTC is? GPS is broadcast, but nobody does time stamping in GPS,
and it lacks the force of law that UTC has.
What is the evidence that no one does time stamping in GPS?
The NTP standard mandates UTC time. NTP
On Oct 24, 2010, at 6:19 PM, Warner Losh wrote:
...GMT is used interchangeably with UT1 and UTC today. If UTC's definition
changes, which one will it follow? For example, NASA already uses GMT when
they really mean UTC.
Excellent argument for UTC to remain synonymous with GMT. Thanks!
From: Rob Seaman sea...@noao.edu
Subject: Re: [LEAPSECS] Cost: getting rid of GMT discontinuing leap seconds
Date: Sun, 24 Oct 2010 19:35:42 -0700
On Oct 24, 2010, at 6:19 PM, Warner Losh wrote:
...GMT is used interchangeably with UT1 and UTC today. If UTC's definition
changes, which
On Oct 24, 2010, at 6:30 PM, Warner Losh wrote:
And what are these other time scales available today?
I suppose it depends on what time scale means. Start with all the zone
times, of course. Then all the scientific time scales, TT, etc. Engineering
time scales - if one is pedantic,
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