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time resolution (was Re: six-page binary format draft)


At 04:10 PM 11/24/97 GMT, Paul Leyland wrote:
>> > The ISO date format "yyyy-mm-dd hh:mm:ss" is valid for another 9000 
>> Yes, please use that format.  And if you permit 5, 6, 7... digit years,
>> then it has no built in obsolescence at all.
>While we are considering the question, is the second a fine enough
>quantum?  It's not at all obvious to me that it is.  If you permit (but
>not require) the seconds field to have a decimal fraction portion we get
>around that limitation as well.  The binary format might represent the
>fraction as, say, integer number of nanoseconds.

I argued at one point to cut it off at 1 minute.

I'm fond of pointing out that Rivest and Lampson did for namespaces what 
Einstein did for spacetime.  It's time we pay attention to old fashioned 
Relativity here, too.

There is no global spacetime.  It is not possible to synchronize clocks.  
The closest we can come to that is with error limits, given our knowledge of 
the minimum and maximum delay in getting a time report.  If there were the 
master atomic clock on the net that still doesn't give us sub-second 
resolution of time setting.

On the other hand, we can be reasonably sure of getting clocks to agree +/- 
30 seconds, so maybe 1 minute resolution of times would be appropriate.

 - Carl

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