Talk:ISO 8601

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Text and/or other creative content from ISO 8601 usage was copied or moved into ISO 8601 with this edit. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists.

Duration

Does ISO 8601 clarify Year duration, for example if a duration is 3 years, was one of them a leap year? Even more important for Months, if a duration is 3 months, was it Jan, Feb, March — 90 or 91 days, depending on leap year, or July, August, September —92 days? GeorgeHarnish (talk) 15:16, 23 September 2024 (UTC)

“Reference date”

There is no “reference date” in ISO 8601. A conference held on May 20, 1975 briefly appeared in the standard in a section that explains a short history of the Gregorian calendar, but the date never functions as a “reference” in the standard in any way.

This date does not even appear in the wiki article on the history of the Gregorian, last I checked. If someone would like to out it there they are more than welcome to. This date is of means nothing whatsoever when explaining or utilizing the actual standard. 2600:1006:B345:A3D5:9D3F:7A93:DD1F:5215 (talk) 00:51, 27 February 2025 (UTC)

The date in question is 20 May, 1875, not May 20, 1975. This was the date the meter convention was signed. In this case, a convention isn't a meeting, it's a synonym for international treaty. It is the reason the metric system has spread all over the world.

The reason it was mentioned in the standard was to tie the dates in the Gregorian calendar to the real world, because everybody—except 2600:1006:B345:A3D5:9D3F:7A93:DD1F:5215 (talk · contribs)—knows when the Meter Convention was signed. It's better than trying to tie it to the birth of Jesus, because his actual date of birth is uncertain.

But the latest version of ISO 8601 amended in 2022 did not include this. Maybe they decided that the Gregorian calendar is so well known it's enough to just give the name of it, no need to explicitly tie it to the real world. Jc3s5h (talk) 01:23, 27 February 2025 (UTC)

It is still not a “reference date,” regardless of a 8/9 typo. 174.227.250.219 (talk) 15:07, 27 February 2025 (UTC)

Edit warring over reference date

@Jc3s5h: Do you have a reference for, "ISO 8601:2004 established a reference calendar date of 20 May 1875 (the date the Metre Convention was signed), later omitted from ISO 8601-1:2019"?

If yes, could you please provide it while reverting the reversion of your change by anonymous user(s)?

Thanks, DavidMCEddy (talk) 02:11, 27 February 2025 (UTC)

I was able to download British Standard BS ISO 8601-1:2019, which is the same as the ISO standard. Paragraph 4.2.1 "The Gregorian Calendar" makes no mention of the Meter Convention. I also have a download of ISO 8601:2004(E). Paragraph 3.2.1 "The Gregorian Calendar" includes the passage

The Gregorian calendar has a reference point that assigns 20 May 1875 to the calendar day that the “Convention du Mètre” was signed in Paris.

More on who made what edit to the article in another post. Jc3s5h (talk) 11:16, 27 February 2025 (UTC)

The only reversion I made recently was of this edit which changed the short description to include the phrase "GNSS L1standards", which makes no sense. The edits concerning the Convention du Mètre were by a different IP user, and I have neither deleted nor restored the passage about that convention. Jc3s5h (talk) 11:26, 27 February 2025 (UTC)

Can you forget about who made which edits? That doesn't matter: You have a credible source to cite. Make the change you want while citing the source you just cited for me.

This should NOT be a game with winners and losers: The Wikipedia ethic asks us to write from a neutral point of view citing credible sources. Your edit was reverted, because it did not cite a credible source, and the person(s) who reverted it could not find it in the source(s) they found.

Go for it! It's good! DavidMCEddy (talk) 13:38, 27 February 2025 (UTC)

My edit was not reverted. A passage similar to what was removed was introduced by Richardrw (talk · contribs) at 14:54, 14 January 2008 (UTC). In my opinion it was an appropriate addition to the article, because back then the standard mentioned 20 May 1875. The standard does not mention it anymore, so I am content to leave the article as it is. Jc3s5h (talk) 14:13, 27 February 2025 (UTC)

@Richardrw: User:Jc3s5h provided a source for the claim that, "a reference calendar date of 20 May 1875 (the date the Metre Convention was signed)"; see above.

What do you think about adding back to this article some reference to "20 May 1875 (the date the Metre Convention was signed)"?

User:Jc3s5h does not think this is necessary. I think it's useful for helping understand the history. Thanks, DavidMCEddy (talk) 14:30, 27 February 2025 (UTC)

After further research using internet searches, I discovered there is a lot of commotion about tens of millions of people listed in the US social security system who are over 100 years old, and are not identified as dead. As explained by Emily Badger and Minho Kim of The New York Times, "The database includes millions of Americans who are probably dead but who have no death records. But they generally don’t collect checks, as Musk and Trump suggest."^[1]

Separately from Musk and Trump, and not mentioned in The New York Times article, a meme has sprung up on the internet that these are caused by COBOL using May 20, 1875, as an epoch, so when a date is missing, that date is used instead. Some otherwise reliable sources, such as Wired, have picked up this nonsense.^[2] I am not a COBOL expert, but have designed computer hardware that ran COBOL as its bread & butter. I've never heard of May 20, 1875, being used as an epoch for COBOL, and none of the internet stories I've encountered had anything to back up this claim.

I don't want to see this Wikipedia article contribute to this false internet meme, so I'm changing my mind and I now oppose mentioning May 20, 1875, in the article. Jc3s5h (talk) 18:24, 27 February 2025 (UTC)

This isn't false. It's just often poorly explained. The 1875 epoch is not built into the COBOL language itself. It is, however, used in time formats that were commonly used in a lot of database systems written in COBOL. The epoch is not specified in the 2019 edition of ISO 8601 but exists in some older versions (I believe including 2004). I used to do data integrations across security trading data going way back to like the 1930s, and a lot of the databases I'd run into used this style of date format, and it is absolutely true if you mix up "date is missing from this line" with "date in this line has a zero-value", you would end up with "20 May 1875" in your output. Auros (talk) 19:02, 14 March 2025 (UTC)

ISO 8601 has never specified that 0, ‘0’, “0”, empty string or null is the same as date 1875-05-20. Whatever value you believe constitutes a “missing date,” it didn’t “end up” as happening 149 years ago (today) because of ISO 8601. Cite something otherwise, please. 67.235.141.68 (talk) 21:19, 17 March 2025 (UTC)

@Jc3s5h: Thanks for your research and comments. My interpretation of your summary of your recent research is roughly the opposite: I think it would be good to have all this documents in this article, in the article on Metre Convention and in the article on May 20 as a note to the mention of May 20, 1875 as the date of the "Signing of the Metre Convention".

However, it's such a minor point, it may not be worth the time to do this. Your time might be better spent on other tasks. (I think that's true for me, though it would take much more time for me to do this than for you to do it.) DavidMCEddy (talk) 20:25, 27 February 2025 (UTC)

Since I don't own official versions of ISO 8601, I don't think I'd want to be the one to add this information. But I'll be sure to look at May 20 and add the signing of the Meter Convention if it isn't already there. Jc3s5h (talk) 01:01, 28 February 2025 (UTC)

I checked May 20 and the signing of the Meter Convention is already listed. Jc3s5h (talk) 12:22, 28 February 2025 (UTC)

An edit on March 14 added the following claim

ISO 8601:2004 established the epoch or reference date as 20 May 1875 (the date the Metre Convention was signed).

This claim is misleading because the date is not an epoch, although it could be called a reference date (the standard called it a "reference point"). It is also misleading because it fails to state that the reference point is no longer present in the current version.

The edit is sourced to a description of a module apparently by someone named Andrew Main; it isn't clear that this module description is a reliable source. The description does not say ISO 8601 treats May 20, 1875, as an epoch or reference date, just that "By way of epoch, the day on which the Convention of the Metre was signed, which ISO 8601 defines to be 1875-05-20". Main uses May 20, 1875, as the epoch of his/her day count "Chronological Julian Day Number". Although this term is mentioned here and there on the internet, I am unable to find a reliable source for it nor a consensus on what it means, since difference sources seem to assign different meanings to it.

I have reverted the edit.Jc3s5h (talk) 20:40, 14 March 2025 (UTC)

References

[1]
Badger, Emily; Kim, Minho (February 19, 2025). "Millions of Dead People on Social Security? The Agency's Own Data Says Otherwise". The New York Times. Retrieved 2025-02-27.
[2]
Gilbert, David (February 17, 2025). "No, 150-Year-Olds Aren't Collecting Social Security Benefits". Wired. ISSN 1059-1028. Retrieved 2025-02-27.

Duration

“Reference date”

Edit warring over reference date

Why remove a URL?

Dates of updates and amendments?

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