[net.mail] Time zone problems

zben@umcp-cs.UUCP (09/06/83)

 The idea of shipping a "standard" time and date (universal or whatever)
sounds good, but I think there is an argument that the recipient of a
message might like to know the local time of day that the message was
sent.  Of course, the receiving mail program COULD know the time zones
of all possible sites the mail could have been sent from, but I think
it would be a better solution to ship both flavors of dates...

mark@cbosgd.UUCP (09/07/83)

I am almost convinced that the news software is going to have to change
in this respect.  (BST doesn't quite do it, since only polar bears are
in the Bering Standard Timezone; however, Teus' claim that EST also stands
for Eireland Standard Time hits a nerve.)  The date is, after all, primarily
intended for machine consumption, not for humans.  (With mail, on the other
hand, I have never seen a program do anything with a date.)

Adding an SIDate is not the solution.  Nor is using somebody's favorite date
notation - there are already too many different notations.  We already have
a standard mechanism for this, it's called RFC850 (the news standard) and RFC822
(the mail standard with which 850 is compatible).  822 specifies several ways of
giving time zones:

(1) There are a few defined time zones: EST, EDT, CST, CDT, MST, MDT, PST, PDT
(the major 4 American zones and their daylight variations); UT and GMT (both
of which are the same zero offset time).  Several others (including BST for
Bering) were deleted from an older mail standard.

(2) Military time zones: single letters A-Z.

(3) Hour/minute offsets from GMT ( ("+" / "-") 4DIGIT ) e.g. +0800 or -1130.

I see two upward compatible ways to do this.  The first is to put all times
in GMT.  The second is to put all timezones in the +0800 notation.  A hybrid
approach could be arranged so that all timezones other than the above 10
go in the +0800 notation - this would allow Americans to still still use
their familiar time zones yet keep within the standard.  (I do not claim
that such American chauvanism is good; merely that it conforms to 822.)

The disadvantage to using GMT is that times might be harder for people to
read if they care when the message was posted.  Perhaps the local time zone
could be used for the user interface but GMT for interchange.  The advantage
is that it's completely upward compatible.

The disadvantage to the +0800 notation is that, I'm not sure, but I don't
think getdate understands it.  It does understand the Military zones, but
that doesn't do the Australians much good.

	Mark Horton