FW: Timezones for US

[Olson, Arthur David (NCI)]

-----Original Message-----
From:	Sullivan N. Beck [SMTP:sbeck at cise.ufl.edu]
Sent:	Tuesday, July 06, 1999 3:48 PM
To:	tz at elsie.nci.nih.gov
Subject:	Timezones for US


On Solaris 2.6, I noticed that the output from zdump seemed a bit odd.
The first lines are:

US/Eastern  Sat Dec 14 20:45:52 1901 GMT = Sat Dec 14 16:45:52 1901 EWT isdst=0
US/Eastern  Sun Mar 31 06:59:59 1918 GMT = Sun Mar 31 02:59:59 1918 EWT isdst=0
...

I'm sure that 1901 shouldn't be in a wartime timezone.

I checked the northamerica file (which, BTW, contains exactly the same 
rules as are in the 1999d tzdata package).  I see the following lines:

# Rule  NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER/S
Rule    US      1918    1919    -       Mar     lastSun 2:00    1:00    W # War
Rule    US      1918    1919    -       Oct     lastSun 2:00    0       S
Rule    US      1942    only    -       Feb     9       2:00    1:00    W # War
Rule    US      1945    only    -       Sep     30      2:00    0       S
Rule    US      1967    max     -       Oct     lastSun 2:00    0       S
Rule    US      1967    1973    -       Apr     lastSun 2:00    1:00    D
Rule    US      1974    only    -       Jan     6       2:00    1:00    D
Rule    US      1975    only    -       Feb     23      2:00    1:00    D
Rule    US      1976    1986    -       Apr     lastSun 2:00    1:00    D
Rule    US      1987    max     -       Apr     Sun>=1  2:00    1:00    D

# US Eastern time, represented by New York
# Rule  NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER
Rule    NYC     1920    only    -       Mar     lastSun 2:00    1:00    D
Rule    NYC     1920    only    -       Oct     lastSun 2:00    0       S
Rule    NYC     1921    1966    -       Apr     lastSun 2:00    1:00    D
Rule    NYC     1921    1954    -       Sep     lastSun 2:00    0       S
Rule    NYC     1955    1966    -       Oct     lastSun 2:00    0       S
# Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
Zone America/New_York   -4:56:02 -      LMT     1883 Nov 18 12:00
                        -5:00   US      E%sT    1920
                        -5:00   NYC     E%sT    1942
                        -5:00   US      E%sT    1946
                        -5:00   NYC     E%sT    1967
                        -5:00   US      E%sT

Unless I'm missing something, this means that from Nov 18, 1883 to Jan
1, 1920, America/New_York is using the rules named "US".  The problem
is, there are no "US" rule prior to 1918.  A quick glance shows the
same thing for America/Chicago, America/Denver, and America/
Los_Angelas. Should there be another Zone line defining an alternate
rule, or another "US" rule?


---------------------------- Sullivan Beck -----------------------------
sbeck at cise.ufl.edu   | This space reserved for some saying demonstrating
CSE 314E             | great wisdom, wit, or insight.  I'll fill it in
PH : (352) 392-1057  | just as soon as I have any of the above.
Fax: (352) 392-1220  |
------------------- http://www.cise.ufl.edu/~sbeck/ --------------------