Unix Tip: SEPT 9TH DATE UPDATE

[Unix Guru Universe]

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			      UNIX GURU UNIVERSE
			         UNIX HOT TIP

			Unix Tip 2074 - September  5, 2002

		    http://www.ugu.com/sui/ugu/show?tip.today

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SEPT 9TH DATE UPDATE

While this statement is from IBM, Y2K patches and updates
on your flavor of Unix should have been fixed by now.
If you feel you are at risk you may want to
check with the software vendors that you deal with.


### BEGIN IBM MESSAGE ####
As is well known, UNIX time is kept internally in seconds, counting
upward from January 1st, 1970. This number hit 1 million (1,000,000)
in March of 1973, and will hit one billion (1,000,000,000) on
Sun Sep  9 01:46:39 2001 UTC This change, from a number which can be
represented in 9 decimal digits to a 10-digit number, is not
expected to cause any problems for UNIX systems.

The reason is that, excepting for a very limited number of uses, this
value is not stored as decimal digits. Instead, it is stored as an
integer value (a 32-bit binary variable) which can be used safely
until the year 2038. The uses in UNIX of a decimal format for the
"seconds time" value are primarily in portable file formats, such as
tar, cpio, and ar. These formats have always supported at least eleven
decimal (or octal in some cases) digits, easily handling UNIX's
one-billionth "birthday".
.
There are no known problems in any version of AIX with this issue.
.
It is entirely possible that some user applications may be storing or
displaying the "seconds time" as character-based digits rather than as
a binary value. If so, and the field width used to store this value is
limited to nine places, errors will result. IBM recommends immediate
correction of such software. In practice, however, Year 2000 testing
showed most applications storing time this way already understood that
the number of seconds could exceed two billion and had coded
accordingly.
.
We do not anticipate that this is going to be a problem, excepting for
a very limited set of erroneously coded user applications.
.
.
Mark Brown
Senior Technical Staff Member, AIX System Architecture

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Thanks go out to Gene Adams for contacting IBM.



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