Re: ISO 8601 anyone?? - Or just who is this Gregory guy,and why is there a calendar named after him?

["William J. Kammerer" <wkammerer@foresightcorp.com>]

Brian Hayes' problem that he's trying to solve by breaking apart date
components involves "... date-time values that have implied values.  For
example, we might write on a paper document 'April 2001' with some
implied notion of end-of-month or begining-of-month. Or, what is the
standard for encoding a date time for a contract ending on April 30,
2001?"

ISO 8601 provides the complete basic calendar month format CCYY-MM, so
2001-04 would be used for April 2001.  Was Brian sending out that huge
copy of ISO 8601 so someone else could look it up for him? In the W3C
Schema you could use the gYearMonth datatype, which "represents a
specific gregorian month in a specific gregorian year," and has the ISO
8601 lexical form of CCYY-MM.

Finally, Ian Galpin "[notices] that all discussions of date here have
always assumed usage of the Gregorian Calendar without question. Are
there other people on the other side of the world devising systems based
on one of the many other calendar systems still in common usage? If so,
there are problems looming..."

It's a conspiracy.  I've attached some background on the Gregorian
Calendar from an old e-mail posted to EDI-L. Sometimes the Gregorian
calendar is said to measure years of what's politely called the "Common"
era.  Have people already forgotten that this Gregory guy was the pope?
The calendar is now so ubiquitous that we sometimes overlook how
culturally laden it is, marking the years since the Christ event, when -
in orthodox Christology - the Word became flesh.  I predicted that
someone would object to this cultural centrism as long ago as July 2000;
see http://lists.ebxml.org/archives/ebxml-core/200007/msg00002.html.
Congratulations, Ian.

William J. Kammerer
FORESIGHT Corp.
4950 Blazer Pkwy.
Dublin, OH USA 43017-3305
+1 614 791-1600

Visit FORESIGHT Corp. at http://www.foresightcorp.com/
"accelerating time-to-trade"

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• From: "William J. Kammerer" <wkammerer@foresight-edi.com>
• To: <EDI-L@UCCVMA.UCOP.EDU>
• Date: Wed, 8 Jul 1998 14:06:13 -0400

Alex Wolff said:  "I am concerned with the fact that many companies are
fixing the Y2K issues but completely neglecting the Y10K issue.  Why not
fix both right now?  9999 seems so far away, and most of us will
probably not be around by then, but think of all the poor EDI analyst
who will be cursing their predecessors."

C'mon, Alex, surely you must be kidding?  Any human artifact which lasts
8000 years would be considered well-designed.  Cities, writing and
agriculture probably started no more than 8000 Years ago, so
accommodating the next  8000 years is probably sufficient!

On MVS mainframes, I always preferred the SAS programming system
(http://www.sas.com/), so I'm used to keeping my dates as an integer
number of days since Jan 1, 1960. The formatting routines, further, were
good for dates from Jan 1, 1582 till 20,000A.D. (Dates before 1960 were
represented as negative numbers).  The 1582 date is not really a magic
number, but rather the date Pope Gregory XIII took 10 days out of the
Christian calendar to correct a build up of days (which accounts for the
rule that every century year - except those divisible by 400, like
2000A.D. - is not considered a leap year).  Since Queen Elizabeth didn't
like Catholics much, England didn't adopt this new Papist custom much
later till 1752. Thus, providing date functions (like formatting and
difference calculation) to span the time before the Gregorian calendar
would probably have been a waste of time for SAS.

I also like dates which naturally extended the YY parts (of YYMMDD or
YYDDD formats) by treating the YY portion as the number of years since
1900A.D. Thus, the dates used internally in IBM's MVS (such as SMF and
RMF records) were extended to YYYYDDD long ago, where YYYY as 0100
simply means 100 years since 1900, or 2000A.D.

A similar technique has always been used to represent readable dates in
FORESIGHT's SEF files, for example: 06/04/96:10:59:48 looks like it is
non-Y2k compliant, but in 2000A.D., the date-time stamps will appear
something like 06/04/100:10:59:48, where the 100 is number of years
since 1900.  Internally, all of our date-time values have been kept as
the number of seconds elapsed since midnight (00:00:00), January 1, 1970
(the standard DOS/ Windows/UNIX  time_t).  This runs out of room in
2038, I think, but I'll be retired and gone.

William J. Kammerer
FORESIGHT Corp.
6543E Commerce Pkwy.
Dublin, OH USA 43017-3221
(614) 791-1600 (voice)
(614) 791-1609 (fax)
e-mail:  wkammerer@foresight-edi.com
Visit FORESIGHT Corp., the world's leading supplier of EDI productivity
tools, at http://www.foresight-edi.com/

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