From: iang@cs.berkeley.edu (Ian Goldberg)
Date: Wed, 30 Jul 1997 00:56:06 +0800
To: cypherpunks@cyberpass.net
Subject: Re: y2k problem *serious*
In-Reply-To: <199707290054.RAA21755@netcom13.netcom.com>
Message-ID: <5rl6e2$agc@abraham.cs.berkeley.edu>
MIME-Version: 1.0
Content-Type: text/plain



In article <Pine.SUN.3.96.970729103454.11487B-100000@beast.brainlink.com>,
Ray Arachelian  <sunder@brainlink.com> wrote:
>Also, the year 2000 isn't a leap year, but most PC's will think it is.

Sigh.  It boggles the mind how many people know the 100-year exception to the
"divisible by 4" rule, but don't know the 400-year exception to the exception.

>From http://www.boulder.nist.gov/timefreq/faq/q28.htm :

    Is the year 2000 a leap year? 

    The year 2000 will be a leap year. Century years (like 1900 and 2000)
    are leap years only if they are evenly divisible by 400. Therefore, 1700,
    1800, and 1900 were not leap years, but the year 2000 will be a leap year.

    To understand this, you need to know why leap years are necessary in
    the first place. Leap years are necessary because the actual length of
    a year is 365.242 days, not 365 days, as commonly stated. Therefore,
    on years that are evenly divisible by 4 (like 1992, for example) an
    extra day is added to the calendar on February 29th. However, since the
    year is slightly less than 365.25 days long, adding an extra day every
    4 years results in about 3 extra days being added over a period of 400
    years. For this reason, only 1 out of every 4 century years is considered
    as a leap year.

Note that (from http://www.boulder.nist.gov/timefreq/ :)

    The Time and Frequency Division is an operating unit of the Physics
    Laboratory of the National Institute of Standards and Technology
    (NIST). Located in Boulder,Colorado at the NIST Boulder Laboratories,
    the Time and Frequency Division:

    o Maintains the primary frequency standard for the United States.
    o Develops and operates standards of time and frequency.
    o Coordinates U. S. T&F standards with other world standards.
    o Provides time and frequency services for United States clientele.
    o Performs research in support of improved standards and services.

So if NIST says 2000 will be a leap year, that would seem to be "official"
(at least for the US).

   - Ian "who's going to be sorry he bothered responding"