From: imp@bsdimp.com (Warner Losh)
Subject: [TUHS] OT: American Culture
Date: Thu, 4 Jan 2018 10:20:26 -0700 [thread overview]
Message-ID: <CANCZdfpdU+6WET5fNzGY=9vxCOaS9TwrvNe0W0pS5u_3S36mgg@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1801041642570.18998@grey.csi.cam.ac.uk>
On Thu, Jan 4, 2018 at 9:48 AM, Tony Finch <dot at dotat.at> wrote:
> Greg 'groggy' Lehey <grog at lemis.com> wrote:
> >
> > A thing that nobody has mentioned, and for which I can't find a
> > reference easily: didn't System V have time zone offsets the wrong way
> > round? I have some recollection from about 1988.
>
> It's enshrined in POSIX but I believe it goes back earlier than that.
> http://pubs.opengroup.org/onlinepubs/9699919799/functions/tzset.html
>
> As I understand it, POSIX TZ offsets are the wrong way round because it
> was more convenient to omit the sign on the TZ offsets, and because Unix
> comes from America that meant no sign -> west, negative -> east.
>
There's also a time interval measurement convention from the high precision
time keeping world that has negative offsets 'forwards' and positive
offsets 'backwards' which this matches. It sure was confusing to me when I
first encountered it when the time scientists were telling me the
measurements were backwards...
Warner
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next prev parent reply other threads:[~2018-01-04 17:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-03 22:49 Norman Wilson
2018-01-04 2:59 ` Greg 'groggy' Lehey
2018-01-04 16:48 ` Tony Finch
2018-01-04 17:20 ` Warner Losh [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-01-03 2:42 Doug McIlroy
2018-01-03 14:19 ` Random832
2018-01-02 16:43 Clem Cole
2018-01-03 13:25 ` arnold
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