On Wed, 15 Apr 1998, David A. Gatwood wrote:
> Here's a novel concept... how about trashing the binary files for
> timezones, and creating a human-readable file containing the time change
> specs so that people can configure them according to their particular
> situation....

The binary files are generated from human-readable text files (they're
compiled with the "zic" program). If you have the NetBSD source around,
see share/zoneinfo/northamerica or something (you can fetch it off
ftp.netbsd.org if you don't have the source :) 

They can be a bit complicated though... the thing is that the time not
only needs to be correct now, it needs to be correct in the past and
in the future too. (And not only are there more than 24 or 48 or whatever
timezones, the timezone files define the daylight savings time/summer
time switchover dates too).

Anyways, my personal opinion on this whole business is that one isn't
installing NetBSD daily or anything... so what if it's a bit slow?
We should be trying to move to installing from the NetBSD side, which
would probably speed things up more than trying to get rid of a few K
worth of timezone files. Maybe the SCSI drivers themselves could be
sped up too (I don't know about the ncrscsi/sbc drivers, but the esp
driver is currently really slow). That'd give a big performance boost
when you're actually _using_ NetBSD, not just when you're installing
it.


Here's part of the northamerica timezone file, containing the definition
for Central time:

# From Arthur David Olson:
# US Daylight Saving Time ended on the last Sunday of *October* in 1974.
# See, for example, the front page of the Saturday, 1974-10-26
# and Sunday, 1974-10-27 editions of the Washington Post.

# From Arthur David Olson:
# Before the Uniform Time Act of 1966 took effect in 1967, observance of
# Daylight Saving Time in the US was by local option, except during wartime.

# 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 Central time, represented by Chicago
# Rule  NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER
Rule    Chicago 1920    only    -       Jun     13      2:00    1:00    D
Rule    Chicago 1920    1921    -       Oct     lastSun 2:00    0       S
Rule    Chicago 1921    only    -       Mar     lastSun 2:00    1:00    D
Rule    Chicago 1922    1966    -       Apr     lastSun 2:00    1:00    D
Rule    Chicago 1922    1954    -       Sep     lastSun 2:00    0       S
Rule    Chicago 1955    1966    -       Oct     lastSun 2:00    0       S
# Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
Zone America/Chicago    -5:50:36 -      LMT     1883 Nov 18 12:00
                        -6:00   US      C%sT    1920
                        -6:00   Chicago C%sT    1936 Mar  1 2:00
                        -5:00   -       EST     1936 Nov 15 2:00
                        -6:00   Chicago C%sT    1942
                        -6:00   US      C%sT    1946
                        -6:00   Chicago C%sT    1967
                        -6:00   US      C%sT

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