[LEAPSECS] Dava Sobel article about Charlottesville meeting

[Warner Losh]

On Jul 22, 2013, at 6:18 PM, Harlan Stenn wrote:

> "Gerard Ashton" writes:

>> Dava Sobel mention that time displayed on cell phones is consistent.

> 

> That hasn't been my experience.

> 

>> But I just took a course on evaluating emergency exercises where the

>> instructor emphasized the importance of synchronizing watches with the

>> exercise leader, so that records of events by evaluators in different

>> locations can be correlated. The instructor claimed that the times

>> displayed by different cell phones can vary by several minutes.

> 

> That has been my experience.

> 

> I have an NTP app for my iPhone, and so far the most "off" that I've

> seen is 1 minute.  But the clock that controls the displayed time is not

> disciplined well at all.


It all has to do with the phone you get... Some do well, others not so well. Where some is only a tiny sliver of the population.

Cellular *NETWORKS* know what time it is down to the microsecond level, but that isn't want's displayed on the phone...

Warner