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

There is no particular difficulty in getting synchronization down to the 
millisecond level with NTP (RFC 1305).

Donald

On Mon, 24 Nov 1997, Carl Ellison wrote: 

> Date: Mon, 24 Nov 1997 15:23:50 -0500
> From: Carl Ellison <cme@cybercash.com>
> To: Paul Leyland <pcl@sable.ox.ac.uk>
> Cc: apb@iafrica.com, spki@c2.net
> Subject: time resolution (was Re: six-page binary format draft)
> 
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> 
> 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 
> years.
> >> 
> >> 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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> 
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