To whom it may concern,

I am writing to report an issue I have discovered in the recent change to the Asia/Dhaka time zone data, which recently implemented daylight saving time in June. The recent update to the time zone data (tzdata2009j) includes a start date for daylight saving time, but no end date. Intuitively, daylight saving time should have a start and an end date within the same year, otherwise what is implemented is an indefinite GMT offset change. Because of this programs that detect DST rules may see the absence of an end to the DST period as an error. This may cause programs which obtain DST rules using Olson time zone data to fail to detect daylight saving time rules for Asia/Dhaka. For completeness, I propose a tentative end date be implemented now, and an updated date be implemented once an official date is released, or the government releases an additional tentative date in September.

According to timeanddate.com:

        "The press secretary did not confirm the length of DST but stated that the government would decide the DST end date and would announce it later. On another note, Bangladesh's minister for power said earlier in 2009 that the new timing might                 continue until the end of September. Timeanddate.com will provide an update on the DST end date when it becomes available. "

 (http://www.timeanddate.com/news/time/bangladesh-daylight-saving-2009.html):

Timeanddate.com picked September 25th, which seems like a likely enough date. I have update the tzdata on my system with the following rules to implement this change.

# Rule  NAME    FROM    TO      TYPE    IN      ON      AT             SAVE    LETTER/S
Rule        Dhaka09        2009        max        -        Jun        19        23:00        1:00        D
Rule        Dhaka09        2009        max        -        Sep        26        00:00        0:00        S                                                        

# Zone        NAME                GMTOFF        RULES        FORMAT        [UNTIL]
Zone        Asia/Dhaka        6:01:40 -        LMT        1890
                        5:53:20        -        HMT        1941 Oct    # Howrah Mean Time?
                        6:30        -        BURT        1942 May 15 # Burma Time
                        5:30        -        IST        1942 Sep
                        6:30        -        BURT        1951 Sep 30
                        6:00        -        DACT        1971 Mar 26 # Dacca Time
                        6:00        Dhaka09        B%sT                    # Bangladesh Time

Could you please evaluate this change for inclusion in the Olson time zone data? Please let me know if you have any questions or concerns.

Thanks,

Nik