Re:Falsehoods programmers believe about Unix time
by msla on Wednesday May 15, 2019 @07:02PM
(#19924634)
My point is this: Most people don't know about UTC/TAI/UT1 or any other standard. They know what's common knowledge, and what's common knowledge is that one day is 24 hours precisely, one hour is sixty minutes precisely, and one minute is sixty seconds precisely. Therefore, when writing software to interface with most people, including businesses with contracts defined in terms of those time definitions, one day is 24 hours or else you end up with problems.
Re:Falsehoods programmers believe about Unix time
by FabHK on Friday May 17, 2019 @05:36PM
(#19943799)
That's why I advocate using UT1 in programming (like Julia), where all of the above is true. The cost we pay for that is that a UT1 second is not exactly a SI second, but I don't see how that matters except in GPS etc.
In TAI: A day is 24 hours (86400 seconds always), and a second is a SI second.
In UTC: A day is a rotation of the earth, and a second is a SI second. (And since these are incompatible, we have to introduce leap seconds).
In UT1: A day is a rotation of the earth, and a second is 1/86400 of a rotation of the earth.
Julia, interestingly, uses the UT1 notion, thus avoiding leap seconds, IIRC.