Using time zone UTC-5 (or GMT-5, or EST5)

[Bill Davidsen]

I am getting some data on mountable media, and the device which writes the files 
runs in EST or whatever you want to call five hours west of Greenwich with no 
daylight time. The problem is that on a FAT or ISO-9660 filesystem, the date and 
time seem to all jump an hour during daylight time. Is there a better way to get 
the time correct than to run a separate system which doesn't use daylight savings?

I have tried exporting TZ=EST5 (or EST or UTC-5 or GMT-5) to the mount command 
or the rsync command, that doesn't seem to help anything, I need the incoming 
data treated as EST, while the machine is at EST5EDT.

-- 
Bill Davidsen <davidsen(a)tmr.com&gt;
   We are not out of the woods yet, but we know the direction and have
taken the first step. The steps are many, but finite in number, and if
we persevere we will reach our destination.  -me, 2010

[Tim]

Allegedly, on or about 24 April 2013, Bill Davidsen sent:
>  No Windows involved, just some data logging machinery which writes
>  info in VFAT or ISO-9660 formats depending on the nmodel. But no
>  daylight changes on the big boxes, I just have to make the data be
>  local time for reports and comparison. The simple way is to run EST on
>  the system which reads to data into Linux. Linux is a tad too smart
>  here.  
What about running them on GMT?  Let your data analyser convert GMT log
times to the timezone of your choice.  Other servers run that way (all
their logs are done in GMT).

-- 
[tim@localhost ~]$ uname -rsvp
Linux 3.8.4-102.fc17.x86_64 #1 SMP Sun Mar 24 13:09:09 UTC 2013 x86_64

All mail to my mailbox is automatically deleted, there is no point
trying to privately email me, I will only read messages posted to the
public lists.

[Rick Stevens]

On 04/24/2013 12:01 PM, Bill Davidsen issued this missive:
>  Rick Stevens wrote:
> > On 04/23/2013 03:31 PM, Bill Davidsen issued this missive:
> >> I am getting some data on mountable media, and the device which writes
> >> the files runs in EST or whatever you want to call five hours west of
> >> Greenwich with no daylight time. The problem is that on a FAT or
> >> ISO-9660 filesystem, the date and time seem to all jump an hour during
> >> daylight time. Is there a better way to get the time correct than to run
> >> a separate system which doesn't use daylight savings?
> >>
> >> I have tried exporting TZ=EST5 (or EST or UTC-5 or GMT-5) to the mount
> >> command or the rsync command, that doesn't seem to help anything, I need
> >> the incoming data treated as EST, while the machine is at EST5EDT.
> >
> > Hopefully you have the "System clock uses UTC" set on your Linux system.
> > If so, then all internal timestamps use UTC. They are converted to local
> > time when displayed (via "ls" or whatever). Winblows boxes don't do
> > that...they use the local time as the timestamp mechanism, so there's
> > the rub (also the cause of many issues with dual-booting machines).
> >
> > You can either set your Linux box to not use UTC as the system clock
> > (I don't like that) or just deal with the idiocy that is Windows. It's
> > your system and your call.
>
>  No Windows involved, just some data logging machinery which writes info
>  in VFAT or ISO-9660 formats depending on the nmodel. 
That equipment probably still uses localtime (if it's DOS- or
CP/M-based). I just used Windows as an example as it is known to cause
this sort of problem.

>  But no daylight
>  changes on the big boxes, I just have to make the data be local time for
>  reports and comparison. The simple way is to run EST on the system which
>  reads to data into Linux. Linux is a tad too smart here. 
Actually, using UTC as the core gives all systems a consistent view of
the current time, regardless of where they're located. The Unix epoch
time is 00:00:00 1 January 1970 UTC after all.

Converting this UTC time to local when displayed is a convenience for
us humans.
----------------------------------------------------------------------
- Rick Stevens, Systems Engineer, AllDigital    ricks(a)alldigital.com -
- AIM/Skype: therps2        ICQ: 22643734            Yahoo: origrps2 -
-                                                                    -
-   To understand recursion, you must first understand recursion.    -
----------------------------------------------------------------------

[Bill Davidsen]

Rick Stevens wrote:
>  On 04/23/2013 03:31 PM, Bill Davidsen issued this missive:
> > I am getting some data on mountable media, and the device which writes
> > the files runs in EST or whatever you want to call five hours west of
> > Greenwich with no daylight time. The problem is that on a FAT or
> > ISO-9660 filesystem, the date and time seem to all jump an hour during
> > daylight time. Is there a better way to get the time correct than to run
> > a separate system which doesn't use daylight savings?
> >
> > I have tried exporting TZ=EST5 (or EST or UTC-5 or GMT-5) to the mount
> > command or the rsync command, that doesn't seem to help anything, I need
> > the incoming data treated as EST, while the machine is at EST5EDT.
>
>  Hopefully you have the "System clock uses UTC" set on your Linux system.
>  If so, then all internal timestamps use UTC. They are converted to local
>  time when displayed (via "ls" or whatever). Winblows boxes don't do
>  that...they use the local time as the timestamp mechanism, so there's
>  the rub (also the cause of many issues with dual-booting machines).
>
>  You can either set your Linux box to not use UTC as the system clock
>  (I don't like that) or just deal with the idiocy that is Windows. It's
>  your system and your call. 
No Windows involved, just some data logging machinery which writes info in VFAT 
or ISO-9660 formats depending on the nmodel. But no daylight changes on the big 
boxes, I just have to make the data be local time for reports and comparison. 
The simple way is to run EST on the system which reads to data into Linux. Linux 
is a tad too smart here.

-- 
Bill Davidsen <davidsen(a)tmr.com&gt;
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

[Bill Davidsen]

staticsafe wrote:
>  On 4/23/2013 18:31, Bill Davidsen wrote:
> > I am getting some data on mountable media, and the device which writes
> > the files runs in EST or whatever you want to call five hours west of
> > Greenwich with no daylight time. The problem is that on a FAT or
> > ISO-9660 filesystem, the date and time seem to all jump an hour during
> > daylight time. Is there a better way to get the time correct than to run
> > a separate system which doesn't use daylight savings?
> >
> > I have tried exporting TZ=EST5 (or EST or UTC-5 or GMT-5) to the mount
> > command or the rsync command, that doesn't seem to help anything, I need
> > the incoming data treated as EST, while the machine is at EST5EDT.
> >
>  Something I found on a quick google search:
>  http://sabg.tk/wiki/config:vfat
>  which leads to:
>  http://www.osnews.com/story/9681/
>
>  Perhaps helpful?
>  
Perhaps. I have to play with it a bit to see what it does in practice before I 
fully trust it to work, but the information is useful in any case.

-- 
Bill Davidsen <davidsen(a)tmr.com&gt;
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

[Rick Stevens]

On 04/23/2013 03:31 PM, Bill Davidsen issued this missive:
>  I am getting some data on mountable media, and the device which
> writes
>  the files runs in EST or whatever you want to call five hours west of
>  Greenwich with no daylight time. The problem is that on a FAT or
>  ISO-9660 filesystem, the date and time seem to all jump an hour during
>  daylight time. Is there a better way to get the time correct than to run
>  a separate system which doesn't use daylight savings?
>
>  I have tried exporting TZ=EST5 (or EST or UTC-5 or GMT-5) to the mount
>  command or the rsync command, that doesn't seem to help anything, I need
>  the incoming data treated as EST, while the machine is at EST5EDT. 
Hopefully you have the "System clock uses UTC" set on your Linux system.
If so, then all internal timestamps use UTC. They are converted to local
time when displayed (via "ls" or whatever). Winblows boxes don't do
that...they use the local time as the timestamp mechanism, so there's
the rub (also the cause of many issues with dual-booting machines).

You can either set your Linux box to not use UTC as the system clock
(I don't like that) or just deal with the idiocy that is Windows. It's
your system and your call.
----------------------------------------------------------------------
- Rick Stevens, Systems Engineer, AllDigital    ricks(a)alldigital.com -
- AIM/Skype: therps2        ICQ: 22643734            Yahoo: origrps2 -
-                                                                    -
- "I was contemplating the immortal words of Socrates when he said,  -
- 'I drank WHAT?'"                   -- Val Kilmer in "Real Genius"
 -
----------------------------------------------------------------------

[staticsafe]

On 4/23/2013 18:31, Bill Davidsen wrote:
>  I am getting some data on mountable media, and the device which
> writes
>  the files runs in EST or whatever you want to call five hours west of
>  Greenwich with no daylight time. The problem is that on a FAT or
>  ISO-9660 filesystem, the date and time seem to all jump an hour during
>  daylight time. Is there a better way to get the time correct than to run
>  a separate system which doesn't use daylight savings?
>  
>  I have tried exporting TZ=EST5 (or EST or UTC-5 or GMT-5) to the mount
>  command or the rsync command, that doesn't seem to help anything, I need
>  the incoming data treated as EST, while the machine is at EST5EDT.
>   
Something I found on a quick google search:
http://sabg.tk/wiki/config:vfat
which leads to:
http://www.osnews.com/story/9681/

Perhaps helpful?
-- 
staticsafe
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