On Fri, Mar 27, 2009 at 11:53 AM, Paul E Condon
<pecondon@mesanetworks.net> wrote:
OT question: I think the actual, underlying time data source for email
time is the Unix time clock on the originator's host. This gets
translated into a text string for insertion into the email. I think
the format of this string is supposed to have time zone info in it, so
it should be possible to know what the actual UTC time of sending was,
but ... suppose you are looking at old emails in an archive. Suppose
it matters to the minute when that old email was actually sent, like
in a criminal or national intelligence investigation. Is there a
database somewhere that records the dates of switching to and from
summer time in each locale for each year in the past? For instance,
time/dates from early March in the Mountain time zone were in MDT this
year but should not be treated as MDT for the year 1980. How could
an investigator, or historian/archivist, deal with this?
The Olson database (zoneinfo database), which is the standard source of time zone info on Linux, attempts to record all time zone changes since 1970.
http://en.wikipedia.org/wiki/ZoneinfoJosh Kelley