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Re: bohe and delta experimentation...

From: Poul-Henning Kamp <phk@phk.freebsd.dk>
Date: Fri, 18 Jan 2013 11:22:31 +0000
To: Amos Jeffries <squid3@treenet.co.nz>
cc: ietf-http-wg@w3.org
Message-ID: <22175.1358508151@critter.freebsd.dk>
Content-Type: text/plain; charset=ISO-8859-1
In message <50F91424.6090804@treenet.co.nz>, Amos Jeffries writes:

>Noting that the Julian calendar was deprecated around 400 years ago. We 
>are on Greogrian calendar these days.

The rumours of MJDs demise are certainly premature ;-)

There is one particular compelling argument for using a day-based
time representation:  It makes it possible communicate clearly when
faced with unpredictable leap-seconds.

A six byte format could be:

	Day			16 bits
	Fractional-Day		32 bits

The Day would be counted relative to a recent epoch (dec 21 2012 ? :-)
which would give us 179 years range into the future.

Time of day would be counted in units of 25 microseconds since
midnight UTC.  (A one byte shorter alternative would count in units
of 10 milliseconds.)

The crucial trick is that the fractional day field is an incomplete
radix, which leaves room for the variable length of day forced on us
with the current definition of UTC, while at the same time using
the day as the primary radix, allowing POSIX compliant operating
systems to not get confused.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.
Received on Friday, 18 January 2013 11:22:58 UTC

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