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Several threads have discussed the accuracy of time calculated using
script when Daylight Saving Time (DST) is considered. A page at
http://webexhibits.org/daylightsaving/ gives much information on DST,
and how it differs in various parts of the world. There is a calculator
for the US and EU systems. However there are other variations in the
world.
In the US, I live in the CST time zone. However this is called CDT when
DST is in effect. Not all of the US has DST. You must remember that the
US is huge, some of our states are larger than most European countries,
and the system of government is a complex mixture of federal, state,
and local levels of law. There is even tribal law for some native
American reservations. Thus it should come as no surprise that usage of
DST is not uniform in the US. DST is not observed in Hawaii, American
Samoa, Guam, Puerto Rico, the Virgin Islands, and most of the Eastern
time zone of the state of Indiana and the state of Arizona (excluding
the Navajo Indian Reservation that spans parts of 3 states and uses
DST).
DST seems to have been first widely used in both Europe and the US at
the time of WWI.
The concept of starting the day early and retiring early perhaps first
was given by Benjamin Franklin when he was an American delegate in
Paris in 1784. He based his argument on savings of fuel for lighting in
an essay "An Echnomical Project" written in Paris. The link given has a
link to the full essay.
The variation in DST in the US is a real problem for nation-wide
services such as satellite TV that download program schedules. This is
solved in the setup by the user or installer selecting if the area uses
DST or not. Likewise, most ISPs in the US allow such a selection so
that their clock is accurate.
script when Daylight Saving Time (DST) is considered. A page at
http://webexhibits.org/daylightsaving/ gives much information on DST,
and how it differs in various parts of the world. There is a calculator
for the US and EU systems. However there are other variations in the
world.
In the US, I live in the CST time zone. However this is called CDT when
DST is in effect. Not all of the US has DST. You must remember that the
US is huge, some of our states are larger than most European countries,
and the system of government is a complex mixture of federal, state,
and local levels of law. There is even tribal law for some native
American reservations. Thus it should come as no surprise that usage of
DST is not uniform in the US. DST is not observed in Hawaii, American
Samoa, Guam, Puerto Rico, the Virgin Islands, and most of the Eastern
time zone of the state of Indiana and the state of Arizona (excluding
the Navajo Indian Reservation that spans parts of 3 states and uses
DST).
DST seems to have been first widely used in both Europe and the US at
the time of WWI.
The concept of starting the day early and retiring early perhaps first
was given by Benjamin Franklin when he was an American delegate in
Paris in 1784. He based his argument on savings of fuel for lighting in
an essay "An Echnomical Project" written in Paris. The link given has a
link to the full essay.
The variation in DST in the US is a real problem for nation-wide
services such as satellite TV that download program schedules. This is
solved in the setup by the user or installer selecting if the area uses
DST or not. Likewise, most ISPs in the US allow such a selection so
that their clock is accurate.