[net.puzzle] Computer bugs and the year 2000

lipp@mariah.DEC (Nicki Lipp - DTN 522-2320) (01/24/85)

<>

I have heard that some software take into the account that the year 2000
is a leap year when indeed it is NOT a leap year.  The computers can
roll over to that year, but will be off by one day after February 28th...

jlg@lanl.ARPA (01/25/85)

> <>
> 
> I have heard that some software take into the account that the year 2000
> is a leap year when indeed it is NOT a leap year.  The computers can
> roll over to that year, but will be off by one day after February 28th...

But 2000 AD IS a leap year!  It's divisible by 400.  The rule is:

leap year every four years (year number divisible by 4)
except every 100 years (year number divisible by 100)
except every 400 years (year number divisible by 400)
...

I think there is another exception, but it's on 4000 years or something
and won't occur in my lifetime.

It's interesting to note that the rule of having leap year every four years
except every 128 years would be accurate for over 30,000 years.  The orbital
elements of the earth would probably change noticably before then.

J. Giles

msb@lsuc.UUCP (Mark Brader) (01/28/85)

> I have heard that some software take into the account that the year 2000
> is a leap year when indeed it is NOT a leap year.  The computers can
> roll over to that year, but will be off by one day after February 28th...

As somebody else pointed out, 2000 IS a leap year -- it's 2100 that isn't.
Notice that the quoted article was posted from a DEC site.  Does this mean
that users of DEC operating systems can expect their machines to try to
skip the date February 29, 2000? :-)

Mark Brader

adm@cbneb.UUCP (02/07/85)

>  /***** cbnap:net.puzzle / decwrl!lipp /  6:50 pm  Feb  6, 1985 */
>  <>
>  
>  I have heard that some software take into the account that the year 2000
>  is a leap year when indeed it is NOT a leap year.  The computers can
>  roll over to that year, but will be off by one day after February 28th...
>  /* ---------- */

Wrong!  The year 2000 is a leap year (1900 was not).  Every century year
is not a leap year UNLESS it is divisible by 400.