Ask Slashdot: How Many Time Standards Are There?

jjoelc writes "Being one of those 'suffering' through the time change last night, the optimist in me reminded me that it could be much worse. That's when I started wondering how many different time/date standards there really are. Wikipedia is a good starting point, but is sorely lacking in the various formats used by e.g. Unix, Windows, TRS-80, etc. And that is without even getting into the various calendars that have been in and out of use throughout the ages. So how about it? How many different time/date 'standards' can we come up with? I'm betting there are more than a few horror stories of having to translate between them..."

Comments

Excel's year 1900 bug

[Blaskowicz]

Excel is known for considering year 1900 as a leap year even though it's not, but I don't know if this historical bug (carried over from Lotus 1-2-3 according to wikipedia) is still respected. So consider Excel usable to year 1901 to a date I don't know.
Likewise the Y2K38 problem with Unix is that time, if represented with 32 bits, doesn't go before a certain 20th century date as well as ending abruptingly on a certain date and time in 2038 - causing the end of the world. Both examples mean that you have to pay attention to the usable time range - be it usable length, absolute minimum date, absolute maximum date, with hopefully some time standards offering infinite range (like A.D. / C.E. year numbering?)

Leap seconds is another infuriating problem and relativity in general and I have to wonder if we have to consider Mars's time, Earth's time, Sun's time, Voyager 2's time etc. in any relevant way. Have fun!

GPS Time

[Anonymous Coward]

Another interesting one is GPS-Time, which is basically UTC without the leap seconds.

https://en.wikipedia.org/wiki/GPS_time#Timekeeping

RFC2550 Compliance

[Mr. Sketch]

We have quite a lot of them, but we don't have many systems that are fully RFC2550 Compliant:
https://tools.ietf.org/html/rfc2550

Re:stop worrying about time

[AvitarX]

This is what happens when you don't.

http://infiniteundo.com/post/25509354022/more-falsehoods-programmers-believe-about-time-wisdom

Re:Time Standards vs. Time Formats, and Y10K probl

[meustrus]

24 and 60 were not arbitrary. They were chosen by ancient Babylonians because they are cleanly divisible by many numbers; 24 by 2, 3, 4, 6, 8, and 12, and 60 by 2, 3, 4, 5, 6, 10, 12, 15, 20, and 30. It was important to be able to divide time cleanly because they didn't have fractions or decimals at the time. Citation needed, of course, but I don't have time to find a source and this is something I remember from when I was a kid.