[LEAPSECS] Meeting with Wayne Whyte

Tim Shepard shep at alum.mit.edu
Tue Feb 1 16:51:56 EST 2011

> They might just call the new leap-less timescale


> "Unified Time for Communication"


> To shut up one particular loud astronomers claims of propertyrights

> and TLAs.

If indeed leap seconds are abolished by the ITU, I am very much in
favor of a name change for the time scale.

The name change serves as an alert to those who made engineering
decisions based on the definition (with no explicit expiration date)
of the timescale and its promise to remain within 0.9s of UT1.

Choosing a new name that happens to have the same TLA would not be my
preference, but changing the name to something that happens to have
the same TLA is preferable to no name change at all.

Idle Question: If they were to replace Coordinated Universal Time
with Unified Time for Communication, would those jurisdictions which
adopted Coordinated Universal Time for legal civil time automatically
switch to Unified Time for Communication because the TLA happens to
be the same? I would think not.

If the ITU starts promulgating standards for Unified Time for
Communication, perhaps some other body could take up the continued
maintenance (with leap seconds) of Coordinated Universal Time.

If the ITU just simply abolishes leap seconds, and continue to call
Coordinated UT without leap seconds Coordinated Universal Time, then
they will have lost some credibility as a standards setting

If this happens, I fully expect some folk will decide that it is
easier to continue to run their systems on some close approximation
of UT, and we will see some NTP servers continue ticking some
approximation to UT (perhaps very much like what UTC is today) while
others go off on a new time scale which is some fixed offset from
TAI. Unfortunately, the NTP protocol has no good way of carrying any
indication of which time scale it is carrying, so at the boundaries
(where an NTP server from one camp is communicating with an NTP
server in the other camp) there will be some unfortunate SNAFUs.

I believe NTP does have a way for stratum 1 NTP servers to indicate
how they are getting time, at least through administrative protocol
interfaces if not the protocol itself, but that doesn't get passed
along through the stratums, and certainly was not contemplated as a
way of distinguishing different time scales when the protocol was

Proposing a rev of the NTP protocol to add this information would not
obviously help, because the rationale for continuing to run some NTP
servers and clients on a good approximation to UT will be precisely
because it is easier to do that than to try and update software
(firmware?) inside those systems. If you could update to a new
revision of the NTP protocol, then you could presumably update the
system to no longer depend on the difference between UTC and UT1
being bounded.

-Tim Shepard
shep at alum.mit.edu

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