RE: Year 300 bug in ILE RPG or ...? (Again)

[Buck Calabro <mcalabro@xxxxxxxxxxxx>]

On Wednesday, May 27, 1998 1:10 PM, bvining@VNET.IBM.COM 
[SMTP:bvining@VNET.IBM.COM] wrote:
> Dean,
>
> I realize you're simply playing Devils Advocate here, and I am
> definitely
> out of any area I can claim expertise in, but I can only think of two
> methods that a historian/archeologist/etc. could use to determine a
> given
> date out of the past.  One would be using a technology such as carbon
> dating (or whatever is used these days), the second would be to find an
> artifact with a date on it.
>
> In the case of technology, I usually see dates that are plus or minus
> a few ten/hundred/thousand/million years so I doubt many applications
> will try to set a particular day within a year (and then have a
> dependence on the accuracy of that date).

-snip-

Bruce,
        Excellent discussion!  There are several other ways to determine 
ancient 
dates to the very day: Proclaimation on Death Taxes, the 293rd day of the 
reign of Caesar Augustus, blah blah blah.  This was a very common way to 
date transactions and documents for several millennia.  One can accurately 
date astronomical events to the day based upon the recording of 
eclipses/occultations, etc.

Historical dates are often used for comparison purposes: Did Henry II live 
before Louis VI?  Did his famous "Peace with the French" speech before 
Parliament come before Louis dispatched the troops?  In such cases, 
converting their birth/death dates to "Gregorian" is a useful common 
denominator, even though none of the dates can strictly be expressed as a 
Gregorian date.  Likewise, dates in the 2nd century can be useful when 
trying to do comparative timelines from different countries.  In these 
cases, dates are converted from "local" to "Gregorian" simply to 
facilitate comparisons within a familiar framework.

Astronomers use another date system (I *think* it's called Lilian, but am 
not sure.)  This system picks an arbitrarily old date (like 1 Jan 4000BCE) 
and calls it 1.  The date increments by one every day.  1 Jan 2000CE is 
2,451,545.  27 May 1998CE is 2,450,961.

So... there are legitimate reasons to take old dates and express them as 
Gregorian dates.  Having said all that, I'd guess that the big worry is 
converting to native date format and then finding problems with it. 
 Finding one bug manes one wary that there may be more...

Buck Calabro
Commsoft, Albany, NY
mailto:mcalabro@commsoft.net

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