On 2/15/2008 9:11 PM, Rob Seaman allegedly wrote:
1a) Systems may need a table of leap seconds (after all, that's what
all the kvetching has been about). Will this be required
indefinitely? Maintenance procedures and such?
IBM mainframes have done this for at least 10-20 years. Their
In message [EMAIL PROTECTED], Michael Sokolov writes:
Poul-Henning Kamp [EMAIL PROTECTED] wrote:
This is the point where the POSIX people shot us in the feet by
ignoring leap-seconds.
Why care about POSIX at all? Why not use a non-POSIX UNIX system then?
Because I live in the real world.
--
Because I live in the real world.
POSIX is indeed a facet of the world we've built. I might argue that
better system engineering practices might have avoided its
limitations :-) but we have to deal with the technology we've inherited.
Note, however, that the actual real world is part of
On Fri, 15 Feb 2008, Tony Finch wrote:
For a shorter version see Seidelmann's writeup in
Explanatory Supplement to the Astronomical Almanac,
University Science Books, 1992
Not the more recent edition?
http://www.amazon.com/gp/product/1891389459/
Is that just a paperback version of the 1992
Rob Seaman scripsit:
POSIX is indeed a facet of the world we've built. I might argue that
better system engineering practices might have avoided its limitations
:-) but we have to deal with the technology we've inherited.
Richard P. Gabriel's famous The Rise of 'Worse Is Better' essay
Rob Seaman said:
After all, Princeton is in New Jersey and Watson and Crick reverse
engineered DNA (three billion years of design by the ultimate
committee) over bitters at the Eagle in Cambridge.
A much over-rated pub, in my opinion. There are better places on King
Street.
--
Clive D.W.
Thanks for the pointer. Sounds like an interesting read, I'll look it
up. I suspect I already grasp the gist of the Cambridge versus New
Jersey characterization, but note that there is a lot of cross-
fertilization and most people have responsibilities in both camps.
After all, Princeton
In message [EMAIL PROTECTED], Rob Seaman writes:
So far I have yet to see one single example of non-astronomy software
that needs changed to handle loss of leap-seconds.
And you have access to ATC and nuclear control systems? Has anyone at
Boeing or GE even been informed of the looming doom
Neither the ATC nor the nuclear control systems care about where the
sun or the stars is in the sky.
They may not care for the same reasons that astronomers care, but
let's list a few of the many ways they might care:
1a) Systems may need a table of leap seconds (after all, that's what
On Wed, 13 Feb 2008, Rob Seaman wrote:
The day is a key concept in our civilization. The mean solar day is
the natural way to implement this. Sundials have nothing to do with the
mean solar day, but rather the apparent solar day.
How does the mean solar day relate to ephemeris time? Between
There are a lot of timescales. Astronomers are as heavy users of even
interval time as of Earth orientation time. I guess the answer to
your question lies in the explanatory supplement to the astronomical
almanac. Recent IAU standards changes have yet to appear in a
similarly normative
On Thu 2008-02-14T14:07:52 +, Tony Finch hath writ:
How does the mean solar day relate to ephemeris time?
Again, the interval when the worst chaos reigned as people tried to
figure out how to answer that question is covered in this 1966
document by the geodesist trying to explain it all for
On Thu 2008-02-14T21:53:37 +, Poul-Henning Kamp hath writ:
But even the zoneinfo leapsecond table can not solve the basic
problem telling the two identical time_t values apart.
Which is not henceforth troublesome if time_t becomes TI.
There is far too much code and data out there to even
In message [EMAIL PROTECTED], Steve Allen writes:
There is a distinction. POSIX zoneinfo and its equivalents in other
precison+civil time systems already have the mechanisms to let the
distinction be clear. They can handle both a monotonic interval and a
conversion to and from various epochs
In message [EMAIL PROTECTED], Steve Allen writes:
That's what they said about changing the conventional longitudes of
every observatory on the planet in order to get agreement on the value
of UT starting in 1962. But in 1961 the IAU said do it, and they
did -- even in cases where it caused a
In message: [EMAIL PROTECTED]
[EMAIL PROTECTED] (Michael Sokolov) writes:
: Poul-Henning Kamp [EMAIL PROTECTED] wrote:
:
: This is the point where the POSIX people shot us in the feet by
: ignoring leap-seconds.
:
: Why care about POSIX at all? Why not use a non-POSIX UNIX system
Poul-Henning Kamp [EMAIL PROTECTED] wrote:
This is the point where the POSIX people shot us in the feet by
ignoring leap-seconds.
Why care about POSIX at all? Why not use a non-POSIX UNIX system then?
The time_t type, contains the number of SI seconds since 1970-01-01
00:00:00 UTC
In case folks haven't noticed, Steve and I have each (separately) been
trying to talk about new topics (or, at least, new facets of old
topics :-)
Meanwhile...Poul-Henning Kamp replies:
The heart of civil timekeeping is the dynamic tension between the
two definitions of the second:
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