Talk:Unix time

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Unix time does represent UTC[edit]

The last sentence of the 1st paragraph states: "Due to this treatment, Unix time is not a true representation of UTC."

However, the previous statements and examples underneath indicate that Unix time maps directly to UTC: At any midnight, Unix time is always an integer multiple of 86,400 seconds - which UTC reflects. Unix time and UTC are both adjusted during a leap second event, in the same way by effectively "holding" for a second. In that sense, Unix directly represents UTC.

It would be consistent to delete the word "not" from that confusing sentence, and thus state: "Due to this treatment, Unix time is a true representation of UTC."


Tim Atkins — Preceding unsigned comment added by (talk) 23:22, 29 May 2020 (UTC)Reply[reply]

UTC represents the last second of 2016-12-31 as 23:59:60, with the previous second being 23:59:59. See, for example, ITU-R Recommendation TF.460-6, section Annex 1, section 2 "Leap-seconds", which says, in paragraph 2.2, "A positive leap-second begins at 23h 59m 60s and ends at 0h 0m 0s of the first day of the following month.", and Annex 3, "Dating of events in the vicinity of a leap-second", which shows an example of an event occurring at "30 June, 23h 59m 60.6s UTC".
No time representation that gives those two seconds the same representation can be a true representation of UTC. Guy Harris (talk) 23:37, 29 May 2020 (UTC)Reply[reply]

Guy, thanks for the response. I understand your point here, which is of course valid. When I read the subject sentence I was thinking in context of absolute timescales such as TAI. During the transition you described, Unix time should be considered undefined or invalid; certainly any implementation of Unix time during that transition needs special handling or interpretation. However, apart from these leap-second events, conversion between a UTC representation and its Unix representation is constant; that was my main point. Thanks for clarifying the important exception! — Preceding unsigned comment added by (talk) 22:55, 30 May 2020 (UTC)Reply[reply]

Year 275760 problem[edit]

In JavaScript, the year that can be entered as a Date object is -271821 to 275760 years, and an error occurs when the year exceeds 275760.-- (talk) 09:15, 18 October 2020 (UTC)Reply[reply]

Decimal limits[edit]

Can't really edit, but wanted to add these:

  • At 17:46:39 UTC on Saturday, November 20, 2286, the Unix time value will equal {val|9999999999}} seconds.
  • At 09:46:39 UTC on Wednesday, November 16, 5138, the Unix time value will equal {val|99999999999}} seconds.

These do sometimes come into play, when storing big numbers in decimal formats, or when displaying Unix time in fixed column using decimal digits. I.e. monitoring and tracing tools. 2A02:168:2000:5B:BA6D:8E5D:511E:5578 (talk) 08:38, 2 January 2021 (UTC)Reply[reply]

"1234567890" listed at Redirects for discussion[edit]

Information.svg A discussion is taking place to address the redirect 1234567890. The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 February 24#1234567890 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. 𝟙𝟤𝟯𝟺𝐪𝑤𝒆𝓇𝟷𝟮𝟥𝟜𝓺𝔴𝕖𝖗𝟰 (𝗍𝗮𝘭𝙠) 23:00, 24 February 2021 (UTC)Reply[reply]

It got relisted several times, and ended up at Wikipedia:Redirects for discussion/Log/2021 March 31#1234567890, and finally got closed as "make it a disambiguation page, because there's no consensus". Guy Harris (talk) 07:14, 30 May 2022 (UTC)Reply[reply]

Team-B-Vital Improvement Drive[edit]

Hello all!

This article has been chosen as this fortnight's effort for WP:Discord's #team-b-vital channel, a collaborative effort to bring Vital articles up to a B class if possible, similar to WP:Articles for Improvement. This effort will run for up to a fortnight, ending early if the article is felt to be at B-class or impossible to further improve. Articles are chosen by a quick vote among interested chatters, with the goal of working together on interesting Vital articles that need improving.

Thank you!

Remagoxer (talk) 23:54, 15 October 2022 (UTC)Reply[reply]