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fab23 [soylentnews.org] writes:

Today the xkcd: Y2K and 2038 [xkcd.com] comic was published and this reminded me of the recent very good technical blog post Time is an illusion, Unix time doubly so... [netmeister.org] from Jan Schaumann where he explains how time is handled on different operating systems including some historical background.

As you well know, on Unix systems we measure time as the number of seconds since "the epoch": 00:00:00 UTC on January 1st, 1970. This has made a lot of people very angry and been widely regarded as a bad move.

For starters, this definition is not based on something sensical such as, say, the objective frequency of vibration of a Cesium-133 atom, but on a convenient fraction of the time it takes a particular large rock to complete a full rotation around its own axis.

If you want to learning about any of this:

• Initially the time was measured in 1/60ths of a second
• At least one country has two different utility frequency
• Why Linux will fail again on 23rd April 2262 even with 64-bit counters
• How different operating systems behave around the beginning or end of the epoch
• What will happen with positive or negative leap seconds

then click here [netmeister.org] and read this fine blog posting.

Happy reading and learning!

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