On 2014-01-13 09:29 AM, Michael Deckers wrote:
On 2014-01-12 03:28, Brooks Harris quoted from RFC 5905:Then, and very importantly, Figure 4: Interesting Historic NTP Dates states the relationship to "First day UNIX" - +-------------+------------+-----+---------------+------------------+ | Date | MJD | NTP | NTP Timestamp | Epoch | | | | Era | Era Offset | | +-------------+------------+-----+---------------+------------------+ | 1 Jan -4712 | -2,400,001 | -49 | 1,795,583,104 | 1st day Julian | | 1 Jan -1 | -679,306 | -14 | 139,775,744 | 2 BCE | | 1 Jan 0 | -678,491 | -14 | 171,311,744 | 1 BCE | | 1 Jan 1 | -678,575 | -14 | 202,939,144 | 1 CE | | 4 Oct 1582 | -100,851 | -3 | 2,873,647,488 | Last day Julian | | 15 Oct 1582 | -100,840 | -3 | 2,874,597,888 | First day | | | | | | Gregorian | | 31 Dec 1899 | 15019 | -1 | 4,294,880,896 | Last day NTP Era | | | | | | -1 | | 1 Jan 1900 | 15020 | 0 | 0 | First day NTP | | | | | | Era 0 | | 1 Jan 1970 | 40,587 | 0 | 2,208,988,800 | First day UNIX | | 1 Jan 1972 | 41,317 | 0 | 2,272,060,800 | First day UTC | | 31 Dec 1999 | 51,543 | 0 | 3,155,587,200 | Last day 20th | | | | | | Century | | 8 Feb 2036 | 64,731 | 1 | 63,104 | First day NTP | | | | | | Era 1 | +-------------+------------+-----+---------------+------------------+Please note that this table has to be read with caution. Besides the typo -678,491 for -678,941, one has to realize that "1 Jan -4712" is meant as a date in the Julian calendar, but all the other dates in column 1 must be taken as Gregorian calendar dates, even those before 1582-10-15 -- else the entries in columns 2,3,4 become incorrect. And this makes the entry in column 5 for the date 1582-10-04 incorrect. Michael Deckers. _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Oh dear!I had "worked" the numbers after 1900 to confirm (a pain to do), and was suggesting this table as the normative the link between 1 Jan 1970-First day UNIX and 1 Jan 1972-First day UTC. I had not bothered to verify the earlier values, but its important.
I suppose Mills did this table. I'm sympathectic to how tricky it is to do and confirm these values. It also highlights why due-process is important - the better to catch mistakes like that.
-Brooks
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