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Re: [Scheme-reports] Comments on draft 6

Alex Shinn scripsit:

> As you say, there are generally two uses of monotonic time - as a
> timer, and as a timestamp (and basis for conversion to calendar time).
> POSIX time is completely unusable for the former because it jumps a
> second.

True but irrelevant, because we provide jiffy-based time, which should
be based on monotonic timers if the OS makes them available.

> It is also broken for the latter because it is unable to represent the
> distinction between the first and second repetition of a leap second.
> POSIX time was a mistake that should not be repeated.

Unfortunately, it's what essentially all systems except embedded ones
actually have available.  But I don't wish to rehearse the same debate
that WG1 already had.

> TAI time has neither of these problems - it is clearly the Right
> Thing.

We call the scale we are using TAI, but what it really is is the number
of UTC seconds (which is the same as the number of TAI seconds, which is
the same as the number of SI seconds) since the Posix epoch (which dates
back to before the beginning of UTC).

John Cowan    cowan@x    http://ccil.org/~cowan
If a traveler were informed that such a man [as Lord John Russell] was
leader of the House of Commons, he may well begin to comprehend how the
Egyptians worshiped an insect.  --Benjamin Disraeli

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