[LEAPSECS] Time math libraries, UTC to TAI

[John Sauter]

On Mon, 2016-12-26 at 19:55 -0700, Warner Losh wrote:

> 
> I think it has been too late since the 80's (so we're 30 years too
> late to fix this problem). There's millions of lines of code written
> to POSIX with the mistaken assumption that they are implementing time
> correctly. Changing it all, or even a large part of it, is unlikely
> to
> happen. Without changing the broken APIs, introducing new, non-broken
> ones won't help: people will still be using the bogus APIs. Since
> it's
> impossible to fix all this code, POSIX has, de-facto, defined what
> time is (even though that definition flies in the face of the current
> definition). UTC may well be superior to POSIX's notion, but that's
> entirely besides the point. It's not better enough that people will
> be
> motivated to fix all this code, especially since public education
> about proper (meaning UTC-ly correct) is so lacking. While it might
> result in a better world if POSIX were able to change, it isn't. It
> can't. Efforts in this area are doomed to fail, alas. However, since
> it is a matter of pride for both sides, we'll sadly continue in the
> bogus state where we have the side that has the overwhelming weight
> of
> implementation thinking they are right (or at least not wrong), and
> the side that knows the math and knows their way is better because it
> lacks the flaws of the other guys (but without the mind-share in the
> right places to be implemented correctly universally).
> 
> That's what I mean that POSIX has de-facto changed UTC. It's not a
> value judgement on UTC, per se. The marketplace has effectively voted
> with its feet, and change would be too expensive. Sadly, change on
> either side is seen as too expensive, so we'll likely continue with
> the impedance mismatch until it causes enough major chaos to force a
> change.
> 
> Warner

I do not share your pessimism.  Computer programming is in its infancy:
programmable computers are less than 100 years old.  If UTC will
actually last 1000 years, as I think it will, there is plenty of time
to correct 30 years of badly-written code.  Yes, there are millions of
lines to correct, but we managed the Y2K problem without major
disruption.

We can fix the code that is easy to fix, and write new code correctly. 
Eventually, the amount of bad code will decrease to the point that
instances of bad code will be embarrassing to their maintainers.  That
will be the tipping point after which the amount of bad code will
decline quickly.  It might take take a century or so, but it can be
done.  The increase in the frequency of leap seconds will help: in 1000
years there will be a leap second at the end of each month.

You speak of public education, mind share and the overwhelming weight
of implementation.  Those factors can be overcome.
    John Sauter (John_Sauter at systemeyescomputerstore.com)
-- 
PGP fingerprint E24A D25B E5FE 4914 A603  49EC 7030 3EA1 9A0B 511E
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