[LEAPSECS] Crunching Bulletin B numbers

Joe Gwinn joegwinn at comcast.net
Sat Feb 19 11:04:59 EST 2011

At 10:41 AM -0500 2/19/11, Gerard Ashton wrote:

>On 2/19/2011 10:24 AM, Joe Gwinn wrote, in part:

>>I have not been following the proposal in detail, but a key issue

>>to the POSIX community is that their timescale must be

>>implementable in a totally isolated machine, one having no GPS or

>>internet access.


>>There are other requirements as well. This was discussed at length

>>on the Time Nuts reflector, until Tom kicked the thread over to

>>Leap Secs.


>>Joe Gwinn


>>LEAPSECS mailing list

>>LEAPSECS at leapsecond.com




>I think a description of the totally isolated machine requirement

>would have to be specified

>to make progress. How long would the machine be expected to keep

>good time, what is the acceptable

>tolerance for time of day, and what technology would be used to keep

>time? What is the application

>of the resulting time scale.

These issues were beaten to a pulp in the thread "Leap seconds and
POSIX" around January 2009.

>For example, if the application is time stamping stock exchange transactions

>with the local legal time with a tolerance of 1 second, and the

>technology is the crystal oscillator provided

>by the manufacturer of a commodity PC, that just won't work unless

>the period of isolation is about

>an hour.

If someone really requires such accuracies in an isolated system,
they will have to buy a GPS receiver or an atomic clock, or both.

But that is not the problem POSIX aimed to solve, as POSIX cannot
expect people to have such hardware.

Anyway, this was all discussed at length in ~2009, so some trolling
of the archives is in order if one wishes the new proposal have any
chance with POSIX.

Joe Gwinn

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