[Python-Dev] PEP 418 glossary

R. David Murray rdmurray at bitdance.com
Thu Apr 12 16:54:19 CEST 2012

On Thu, 12 Apr 2012 13:49:43 -0000, =?utf-8?B?S3Jpc3Rqw6FuIFZhbHVyIErDs25zc29u?= <kristjan at ccpgames.com> wrote:
> Wallclock:  This definition is wrong no metter how the BDFL feels about the word.  Please see http://en.wikipedia.org/wiki/Wall_clock_time.

I agree with the BDFL.  I have always heard "wallclock" as referring to
the clock on the wall (that's what the words mean, after all).

When this term became current that meant an *analog* clock that did not
automatically update for daylight savings time, so naturally if you
measure an interval using it it is equivalent to "real time".

However, to my mind the implication of the term has always been that
the actual time value returned by a 'wallclock' function can be directly
mapped to the time shown on the clock on the wall (assuming the computer's
clock and the clock on the wall are synchronized, of course).

Heh.  Come to think of it, when I first encountered the term it was in
the context of one of the early IBM PCs running DOS, which means that
the computer clock *was* set to the same time as the wall clock.

Thus regardless of what Wikipedia thinks, I think in many people's
minds there is an inherent ambiguity in what the term means.   If you
use it to measure an interval, then I think most people would agree
automatically that it is equivalent to "real time".  But outside of
interval measurement, there is ambiguity.

So I think the definition in the PEP is correct.


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