[LEAPSECS] A leap second proposal to consider -- LSEM

Warner Losh imp at bsdimp.com
Wed Nov 3 08:58:04 EDT 2010


On 11/02/2010 23:15, Tom Van Baak wrote:

> So how about having a Leap Second Every Month (LSEM)?

> The definition of UTC doesn't even need to be changed. The

> only question for the IERS each month is if the leap will be

> positive or negative. But there is always a leap; with one or

> many months of notice. It's only 12-bits of data a year. This

> can be disseminated in a modern way (internet).

> No secular drift. No religious objections. No redefinition of

> UTC. No change to WWVB. No change to GPS. No change

> to NTP. No more silly leap second newspapers articles. Way

> more opportunities for software to be written correctly the

> first time. Wider public knowledge and understanding of leap

> seconds. The impetus for creating well-architected internet

> leap second information services. Closer tracking of UT1.

> Greater ability to handle unusual earth accel/deceleration

> episodes.

>

The reference ntp implementation from udel currently has a filter in its
leap second code that restricts leap seconds to June and December.

Many older GPS steered clocks have filters as well that restrict things
to Dec/June and sometimes Mar/Sept.

Some software that listens to WWVB broadcasts "knows" that a leap
indicator means "there will be a leap at the end of December or June."
Not the end of the month. This is a small semantic change. A few years
ago, there were a few of these kinds of broadcast systems knocking about.

Most people will argue with you that this is a change to UTC, despite
monthly leap seconds being in the definition :)

I kinda like the idea, but only if you could publish the leap seconds
years in advance :)

Warner


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