Re: Compute Date Duration

I'have a copy of the first edition of the MI functional reference when
introduced the MI date/time instruction and the scaliger number was 1721424.

In any case it seems that nobody succeded in having a labelled duration with
these date/time instruction.

No ibm'er wrote in the forum just to clarify on this subject, but now  we
know about life, death and miracles of Julius J. Scaliger.

Giuseppe.



----- Original Message ----- 
From: "Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>
To: "MI Programming on the AS400 / iSeries" <mi400@xxxxxxxxxxxx>
Sent: Wednesday, October 19, 2005 2:14 AM
Subject: Re: [MI400] Compute Date Duration


>
> On 17/10/2005, at 7:46 PM, Beppe Costa wrote:
>
> > The MI reference says 1721426 but the C/MI example use 1721424
>
> Scaliger number 1721426 equates to 0001-01-01
>
> Scaliger number 1721424 equates to 0000-12-30 (which is a nonsense date
> because there was no year 0--hence all the confusion with the morons
> who think a new century starts when the zeroes tick over). 1721424
> should be a BC date but CDD converts it to 0000-12-31 when using an SAA
> Calendar.
>
> Given that all dates prior to 14th October 1582 don't allow for the
> "missing" dates they're all wrong anyhow and that's ignoring the
> confusion created by different countries adopting the Gregorian
> calendar at different times.
>
> > #define GREGORIAN_TIMELINE_START  1721424
> >
> > However it seems that both values work the same.
>
> They both work because they are in the same time line--one is just two
> days earlier than the other. The earliest Scaliger number allowed in an
> SAA calendar is 1721060 which equates to 0000-01-01 (nonsense date, see
> above). Anything earlier than that results in MCH1867 with reason code
> 24 "No valid calendar effective date". The correct starting effective
> date is 1721426. The same exception occurs when specifying an ending
> effective date greater than 5373485.
>
> Scaliger numbers go back to sometime in 4000BC (I think) so perhaps
> defining the correct calendar might cause the MI instructions to handle
> earlier dates but I suspect that might not be the case. What business
> reason is there for dealing with such early dates? Scaliger numbers
> also go beyond year 9999 but the 4-digit year restrictions probably
> scupper any attempt to use them.
>
>
> Regards,
> Simon Coulter.
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