[time-nuts] Leap Second results: cheap GPS/1PPS receivers

[Bob Albert]

So I can measure the time interval, which should be one second.  If I measure 10 intervals, my resolution would be 1 part in 10 million.  I think I can set the master oscillator closer than that with beating against WWV. So maybe buying a 1 pps source won't improve anything for me.
 


     On Wednesday, July 1, 2015 2:39 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
   

 
subscriptions at burble.com said:
> My linux boxes also did a double 59:
> Wed Jul  1 00:59:58 BST 2015
> Wed Jul  1 00:59:59 BST 2015
> Wed Jul  1 00:59:59 BST 2015
> Wed Jul  1 01:00:00 BST 2015
> Wed Jul  1 01:00:01 BST 2015 

That's to be expected (unless you have fancy software).

Internally, Linux (and most other modern OSes) use UTC.  The API doesn't 
include the TAI offset.  There is no way to talk about the extra second.

The same problem happens with the switch to summer time.  You need the 
time-zone to tell if the time within the magic extra hour is summer time or 
winter time.  Without the zone, you have to pick one and then there is no way 
to talk about the other one.

To insert the extra second, Linux just sets the time back 1 second, the same 
way you set your clocks and watches back in the fall.



-- 
These are my opinions.  I hate spam.



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