[LEAPSECS] alternative to smearing

[Martin Burnicki]

Michael Rothwell wrote:
> The Gregorian calendar doesn't mess up how computers keep track of time,
> like leap seconds do. Neither do time zones. Leap seconds are different
> -- a special kind of awful.

I think this depends on what your basic time is, and what time you
derive from it.

If the system time runs on UTC, and has current tz rules available, then
you can easily derive local time from UTC. However, without a DST status
you can't distinguish a timestamp like 2:30h in the repeated hour from
the same time 2:30h in the original hour when DST ends.

If your computer ran on local time (like legacy DOS) without a more
monotonic basic time like UTC then you had the same kind of problems
with the end of DST as with a leap second because the basic time is just
stepped back.

On the other hand, if your computer's system time was TAI, and you had a
table of leap seconds ("leap second rules") available, you could do the
conversion to UTC as unambiguously as you can derive a local time from
UTC right now.

So it depends on the implementation.

Martin