Chuck:
I think its something the user is going to have to do themselves . I
would suggest that the users put on the tape label or disk a label
that gives the information you desire.
Then its up to you to read the tape label (user label?) and get the
information from there. Perhaps even a header record.
Outside of that there is no really easy way to determine the
information you desire.
Ed
On Jun 28, 2014, at 1:53 PM, Hardee, Chuck wrote:
Doesn't help, sorry.
Given all the answers I've had so far, all pointing to things
implying real-time conversion of timestamps, I think it is clear
that I haven't stated my need very well.
I have two (currently) sets of data. The data is historical. I have
no control on how the data is produced, it's from a vendor product
which shall remain nameless and is irrelevant. In the previous
version of the product, both sets of data were saved with local
times. In the current product, one set is saved in UTC, the other
in local. The next version will save both sets of data in UTC. That
being said, I need to be able to convert to and from local times
and UTC times. And, let me say now, when I say "time", I mean a
timestamp consisting of yyyy/mm/dd hh:mm:ss.tttttt, that is year,
month, day, hour, minutes, seconds and microseconds.
I currently have routines to determine the range of Daylight
Savings Time, or as some of indicated, Summer Time, and other
names, all boiling down to the same thing.
I have a mechanism to obtain the offset to UTC as a signed value
indicating before or after UTC, for example. On the East Coast of
the US, the UTC offset is -5 hours (non-DST) and -4 hours (DST),
meaning behind UTC.
The issue becomes when I have a local time that falls outside of
the DST period but when adjusted for UTC falls within the DST
period. Does it get adjusted?
For example, given a time of 01:59:59.999999 on the day of the
switch to DST, when the UTC adjustment is made (assuming my US East
Coast example), the time would be 06:59.59.999999. Now, the local
time was outside the DST range, but when adjusted to UTC it falls
within the DST range. Does the adjusted UTC time get adjusted for
DST? And then, having gone thru the narration for local to UTC, a
similar questions exists for UTC to local, and then similar
questions regarding the other end of the DST period.
I hope this better explains what I am looking for.
Chuck
Charles (Chuck) Hardee
Senior Systems Engineer/Database Administration
CCG Information Technology
Thermo Fisher Scientific
300 Industry Drive
Pittsburgh, PA 15275
Direct: 724-517-2633
FAX: 412-490-9230
[email protected]
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-
[email protected]] On Behalf Of Mike Schwab
Sent: Saturday, June 28, 2014 12:49 PM
To: [email protected]
Subject: Re: Local Time conversion to/from UTC Time
Sometimes it helps to see the whole word in a map.
http://www.worldtimezone.com/index24.php
On Sat, Jun 28, 2014 at 11:26 AM, Hardee, Chuck
<[email protected]> wrote:
Yes, I have spent a lot of time there going thru the information
on the web.
I could have easily missed what I was looking for. I will have to
go back thru it and read the compressed files with better scrutiny.
Charles (Chuck) Hardee
Senior Systems Engineer/Database Administration
CCG Information Technology
Thermo Fisher Scientific
300 Industry Drive
Pittsburgh, PA 15275
Direct: 724-517-2633
FAX: 412-490-9230
[email protected]
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-
[email protected]] On Behalf Of John McKown
Sent: Friday, June 27, 2014 9:26 PM
To: [email protected]
Subject: Re: Local Time conversion to/from UTC Time
On Fri, Jun 27, 2014 at 5:28 PM, Hardee, Chuck <
[email protected]> wrote:
John,
I am in the process of writing a program that is reading several
files.
Some of the files have dates in local and some have dates in UTC.
I want to be able to move between the two time bases as needed.
I don't envision the program reading files from differing time
zones at
the same time, but the program could be reading files from any
country in
the world.
Currently I'm concentrating on the US so a US based solution
would be fine
for the moment.
Where I can't seem to get my head to go is related to Daylight
Savings
Time (DST).
If, for instance, the locale is the east coast of the US, the UTC
adjustment would be -05:00, 05:00 UTC is 00:00 local. If the
local time is
02:00 on the day of the switch in the spring, that's easy,
subtract the
signed UTC adjustment from the local time and then add 1 hour.
So, 02:00 -
(-05:00) - 01:00 = 06:00 UTC.
But, what if the local time is 01:59? One would subtract the
signed UTC
adjustment from the local time and then??? So, 01:59 - (-05:00) =
06:59,
but what about Daylight Savings Time? The current local time
being adjusted
is not with the DST range, but the adjusted time via the UTC
adjustment
value is. Does DST come into play here? Is the decision based on
the local
time or the resulting UTC time?
A similar question comes into play on the other end of the DST
range. If
the local time is prior to the end of the DST range, does one
subtract 1
hour from the adjusted time?
Finally, what about the other direction. If one has a UTC time
value, what
are the rules governing the change to a local time with respect
to DST?
I hope my explanation isn't too simplistic. Any thoughts or
direction
might have that would help would be greatly appreciated. That
also goes to
anyone else that might have some input.
Thanks,
Chuck
Charles (Chuck) Hardee
Senior Systems Engineer/Database Administration
Have you looked at the IANA TimeZone Database?
http://www.iana.org/time-zones Wikipedia entry:
http://en.wikipedia.org/wiki/Tz_database
That page has a compressed "text" file which contains a lot of
TimeZone
information. It is public domain. It is what GNU/Linux uses to
adjust the
local time from the UTC values. It has a _lot_ of data in it. It
contains
offsets for time zones and dates within that time zone (i.e. such
as when
the U.S. decided to change when to change to/from DST).
Some Perl code at:
http://search.cpan.org/dist/Date-Manip/lib/Date/Manip/TZdata.pod
Unfortunately, I don't have any example code sitting around. Nor
did I find
any with a simple Google search.
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Mike A Schwab, Springfield IL USA
Where do Forest Rangers go to get away from it all?
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