| Author |
Message |
Paul Allen
Guest
|
 Posted:
Tue Nov 01, 2005 5:41 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
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Dave Martindale wrote:
| Quote: | "paul dot l dot allen at comcast dot net" writes:
Of course the system knows nothing about local time. And I'm
pretty sure my 1997-vintage GPS receiver doesn't know anything
about time zone boundaries. It also has no way for me to tell it
the local offset from UTC. But, I took it out in the front yard this
morning and told it to do a cold start. It thought for a while
and then announced that it knew my location, the current UTC time,
and the correct local time (8 hours behind UTC). How did it do that
if the system didn't know how to tell it my time zone offset?
Some questions:
1) What is your receiver? I'll bet it does have a way to tell it the
local offset from UTC.
|
It's an Eagle Explorer with version 1.4 firmware, dated January 20,
1977. You can bet if you want, but it has no way to set a local offset
from UTC. There's nothing about it in the owner's manual.
| Quote: | 2) What did the receiver think the local time zone was before you did
the cold start? Normally, though a cold start reloads all of the
satellite-provided data, it does not reset user-provided data like
the local timezone offset.
|
It doesn't think anything about the local time zone. It doesn't know
anything about time zones, apparently.
| Quote: | 3) What do you mean by a cold start anyway? Different receivers mean
different things by this.
|
The manual says a cold start erases cached location and time information
and starts over by scanning the sky for satellites. A warm start is
much quicker because the unit can predict the satellites that should
be visible and look just for them.
| Quote: | That's why it's a mistake to embed knowledge of DST transition dates in
software or firmware. Just let NTP or the GPS system take care of it.
But the GPS system, by design, knows nothing of local timezone
boundaries, or the dates DST starts and stops.
|
Although I cannot explain the behavior of my GPS, I think you are
correct. Since neither NTP nor the GPS system can "take care of it",
it appears to be up to software to figure it out.
Paul Allen
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Ron Hunter
Guest
|
| Posted:
Tue Nov 01, 2005 3:22 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
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Paul Allen wrote:
| Quote: | George wrote:
ASAAR wrote:
It will no doubt be much smarter. No longer will MS ask "Where do
you want to go today?" Get ready for "Can't get there from here."
and "You are not authorized to go there." As for insanity, this is
from p.11 of the Nov, 2005 issue of Maximum PC discussing DRM:
Agree, most of what I have read about "Vista" seems to indicate that
the biggest new "features" will be all sorts of DRM controls.
I don't expect Microsoft's next version of Windows to affect me much
more than previous versions have. I don't use it unless there's no
other choice, and there's almost always some other choice.
What does bother me is the apparent push to develop DRM-equipped
hardware that can refuse to operate for an OS or application that
cannot authenticate itself. The authentication method is protected
by an expensive license, precluding its use by open-source
software. Magnetic disk makers have floated such schemes, and
now it seems the next generation of optical drives may have
hardware-embedded DRM. There's an awful lot of money pushing
this, and the current US administration is openly hostile to
the rights of consumers. Most past copy protection schemes have
either failed or been abandoned, but the technological means to
restrict your right to the fair use of content are becoming
increasingly cheap and sophisticated.
Paul Allen
|
All this DRM stuff will have to pass the muster of the marketplace. I
recall a company that 'copy protected' it software disks in such a way
that attempting to copy them rendered both the copy, and original
unreadable. They didn't last long!
HOW does DRM relate to rec.photo.digital, and why cross-post to this NG?
--
Ron Hunter rphunter@charter.net |
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Ron Hunter
Guest
|
| Posted:
Tue Nov 01, 2005 3:26 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
Dave Martindale wrote:
| Quote: | "paul dot l dot allen at comcast dot net" writes:
Of course the system knows nothing about local time. And I'm
pretty sure my 1997-vintage GPS receiver doesn't know anything
about time zone boundaries. It also has no way for me to tell it
the local offset from UTC. But, I took it out in the front yard this
morning and told it to do a cold start. It thought for a while
and then announced that it knew my location, the current UTC time,
and the correct local time (8 hours behind UTC). How did it do that
if the system didn't know how to tell it my time zone offset?
Some questions:
1) What is your receiver? I'll bet it does have a way to tell it the
local offset from UTC.
2) What did the receiver think the local time zone was before you did
the cold start? Normally, though a cold start reloads all of the
satellite-provided data, it does not reset user-provided data like
the local timezone offset.
3) What do you mean by a cold start anyway? Different receivers mean
different things by this.
That's why it's a mistake to embed knowledge of DST transition dates in
software or firmware. Just let NTP or the GPS system take care of it.
But the GPS system, by design, knows nothing of local timezone
boundaries, or the dates DST starts and stops.
Dave
Newer GPS receivers with basemaps can, and probably DO keep track of |
local DST settings, but changing start and stop dates would require a
database update. Best design is to ask the user for his DST offset, and
start and stop dates. Still doesn't account for places like Indiana
where DST is a county-by-county option..... Insane! Your next door
neighbor may have a different time...
--
Ron Hunter rphunter@charter.net |
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Ron Hunter
Guest
|
| Posted:
Tue Nov 01, 2005 3:28 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
Paul Allen wrote:
| Quote: | Dave Martindale wrote:
"paul dot l dot allen at comcast dot net" writes:
Of course the system knows nothing about local time. And I'm
pretty sure my 1997-vintage GPS receiver doesn't know anything
about time zone boundaries. It also has no way for me to tell it
the local offset from UTC. But, I took it out in the front yard this
morning and told it to do a cold start. It thought for a while
and then announced that it knew my location, the current UTC time,
and the correct local time (8 hours behind UTC). How did it do that
if the system didn't know how to tell it my time zone offset?
Some questions:
1) What is your receiver? I'll bet it does have a way to tell it the
local offset from UTC.
It's an Eagle Explorer with version 1.4 firmware, dated January 20,
1977. You can bet if you want, but it has no way to set a local offset
from UTC. There's nothing about it in the owner's manual.
2) What did the receiver think the local time zone was before you did
the cold start? Normally, though a cold start reloads all of the
satellite-provided data, it does not reset user-provided data like
the local timezone offset.
It doesn't think anything about the local time zone. It doesn't know
anything about time zones, apparently.
3) What do you mean by a cold start anyway? Different receivers mean
different things by this.
The manual says a cold start erases cached location and time information
and starts over by scanning the sky for satellites. A warm start is
much quicker because the unit can predict the satellites that should
be visible and look just for them.
That's why it's a mistake to embed knowledge of DST transition dates in
software or firmware. Just let NTP or the GPS system take care of it.
But the GPS system, by design, knows nothing of local timezone
boundaries, or the dates DST starts and stops.
Although I cannot explain the behavior of my GPS, I think you are
correct. Since neither NTP nor the GPS system can "take care of it",
it appears to be up to software to figure it out.
Paul Allen
1977? Seems a bit old for GPS. I thought MINE was old... |
--
Ron Hunter rphunter@charter.net |
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Ron Hunter
Guest
|
| Posted:
Tue Nov 01, 2005 3:31 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
Dave Martindale wrote:
| Quote: | Stewy <anyone4tennis@hotmail.com> writes:
Really? You'd prefer sunrise at 4am and sunset at 4pm? Dumb and dumber!
If sunrise was 4AM, sunset would be 8 PM. If sunset was 4 PM, sunrise
would be 8 AM. Either way, you get equal hours of light before and
after noon.
The point of daylight savings time is to move sunrise/sunset one hour
earlier on the wall clock, so sunrise/sunset is 9 AM/5 PM or 8 AM/6 PM
or 7 AM/7 PM or 6 AM/8 PM or 5 AM/9 PM.
Basically, in the spring the hours of daylight before noon have been
increasing in step with the hours of daylight after noon. Daylight
Savings time "swipes" one of the extra before-noon hours of daylight and
moves it to after noon.
Whether that's an advantage or not depends on your point of view. It
causes schools, stores, and any business with posted hours to
automatically open and close an hour earlier with respect to the sun,
without having to post or remember new hours.
Dave
And causes great physical discomfort for those of us with nice regular |
body clocks....
--
Ron Hunter rphunter@charter.net |
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Dimitrios Tzortzakakis
Guest
|
| Posted:
Tue Nov 01, 2005 7:43 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
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|
--
Tzortzakakis Dimitrios
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "Gary Edstrom" <gedstrom@pacbell.net> ?????? ??? ??????
news:scm9m1l3939pqnrveg0qlog0rcl9pf6r71@4ax.com...
| Quote: | Note: Courtesy copy of this followup sent to author via email.
On Sun, 30 Oct 2005 23:12:59 +0900, Stewy <anyone4tennis@hotmail.com
wrote:
In article <7ek8m1dg6pt1hskd1jrh2np3612rvfgtea@4ax.com>,
Gary Edstrom <gedstrom@pacbell.net> wrote:
Yes, I now that daylight time is a dumb idea, but what are you going to
do?
Really? You'd prefer sunrise at 4am and sunset at 4pm? Dumb and dumber!
The point is that EVERY year I promise myself that I am NOT going to
post this reminder the following year, and EVERY year I ignore my own
advice and post it anyway. I guess I'll never learn!
The ONLY purpose for posting this was as a friendly reminder to people
to adjust their camera clocks, something that is easy to forget. I
didn't intend to start the whole stupid DST discussion over again.
But each year I get a slew private emails back telling me that I don't
need to adjust my cell phone time (Wrong!)...That I don't need to set a
time zone one my GPS (Wrong!)...That I should keep my camera on
GMT...That I should move to Arizona, etc.
Gary
Thanks a lot, I didn't even know that my digital camera had date and time |
settings (Kodak CX 7300) I have it for more than a year so I forgot but how
does it keep that information when I change the batteries?I changed also my
alarm clock, my cell phone, time my computer did it for itself and my
camcorder also (Sony CCD-TR425E PAL)did it for itself also the VCR, the
boombox.
| Quote: | --
Gary Edstrom <gedstrom@pacbell.net
Visit my Midway Island home page at http://gbe.dynip.com/Midway
I am Gates of Borg. Anti-trust laws are irrelevant.
The above tagline is number 207 in a series of 549. Collect them all! |
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Dimitrios Tzortzakakis
Guest
|
| Posted:
Tue Nov 01, 2005 7:44 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
--
Tzortzakakis Dimitrios
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "Bryan Olson" <fakeaddress@nowhere.org> ?????? ??? ??????
news:Aab9f.8159$7h7.7979@newssvr21.news.prodigy.com...
| Quote: | Stewy wrote:
Gary Edstrom wrote:
. Yes, I now that daylight time is a dumb idea, but what are you
going to do?
Really? You'd prefer sunrise at 4am and sunset at 4pm? Dumb and dumber!
Definitely have a look at Luann (www.luannsroom.com) that wants to keep her |
clock at daylight time and gain 2 hours of sleep...
| Quote: |
Sunrise eight hours before noon and sunset four hours after?
Local time, roughly speaking, defines noon as when the Sun is most
directly overhead. Sunrise and sunset are then approximately equally
far from noon. (Earth's elliptical orbit makes the approximation
not-so-good.)
--
--Bryan |
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Dave Martindale
Guest
|
| Posted:
Tue Nov 01, 2005 7:51 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
"paul dot l dot allen at comcast dot net" writes:
| Quote: | Some questions:
1) What is your receiver? I'll bet it does have a way to tell it the
local offset from UTC.
It's an Eagle Explorer with version 1.4 firmware, dated January 20,
1977. You can bet if you want, but it has no way to set a local offset
from UTC. There's nothing about it in the owner's manual.
|
I downloaded the Explorer manual from LEI's website. On page 20, it
says:
Set Local Time
If the time shown on the clock display is not your
local time, change it using the .Set Local Time.
function. To do this, press the MENU key, then
highlight the .Set Clock. label. Press the right arrow
key. The screen at right appears.
Using the right and left arrow keys, move the black
box to the first number in the time that you want
to change. Now press the up or down arrow keys
until the desired number shows. Continue until the
time shown in the display is correct, then press
the ENT key. This enters the new time and erases
the set local time menu.
That's how the receiver knows what time zone you are in. Setting the
local time while the receiver is navigating (and thus knows current UTC)
tells it the timezone offset. Once you set that, it will always use the
same offset - probably across cold restarts too.
On page 9 in the Initialization section it says to enter your local time
to help the process of acquiring satellites. That wouldn't be useful
unless the receiver already had a local time offset, but not the correct
time (because it had been stored without batteries).
| Quote: | It doesn't think anything about the local time zone. It doesn't know
anything about time zones, apparently.
|
It knows the offset between UTC and local time because you (or someone
at the store, or someone at the factory) set the local time manually.
But if you took your unit, flew to a location in another time zone, and
then turned it on, it would show incorrect local time until you changed
it.
Dave |
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ASAAR
Guest
|
| Posted:
Tue Nov 01, 2005 8:42 pm Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Tue, 1 Nov 2005 15:43:10 +0200, Dimitrios Tzortzakakis wrote:
| Quote: | Tzortzakakis Dimitrios
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
. . .
Thanks a lot, I didn't even know that my digital camera had date and time
settings (Kodak CX 7300) I have it for more than a year so I forgot but how
does it keep that information when I change the batteries?
|
Cameras are no different than other devices (such as radios, mp3
players, etc.) that have internal clocks and volatile memory. In
most cases when the main batteries are replaced, voltage is supplied
by a capacitor. In a few cases, a small permanent rechargeable
battery is used instead. The amount of time these can provide to
safely change the batteries varies considerably, ranging from just a
few seconds to more than a month, but it's uncommon to not have at
least several minutes. Now you know enough to get your degree. :) |
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Guest
|
| Posted:
Wed Nov 02, 2005 3:22 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Sun, 30 Oct 2005 11:50:04 -0800, Paul Allen <"paul dot l dot allen
at comcast dot net"> wrote:
| Quote: | Dave Martindale wrote:
"paul dot l dot allen at comcast dot net" writes:
GPS units are fundamentally about knowing the precise time. They get
UTC from the satellites, calculate position by triangulation, and
therefore can calculate local time. I have to believe that the GPS
system knows all about the latest "savings time" rules all over the
planet.
The GPS *system* operates in GPS time. It marches forward at exactly
the same rate as UTC, but GPS time doesn't have leap seconds, so there
are always exactly the same number of seconds in a year, and so GPS time
and UTC differ by an integer number of seconds.
GPS receivers get GPS time from the satellites, plus a data field
giving the current offset between GPS time and UTC, plus a flag
indicating that a leap second is coming. So they have all the
information needed to provide UTC, exactly, if they want to.
But GPS receivers generally don't know what time zone you are in,
because they don't include detailed maps of time zone boundaries. Once
*you* tell the receiver what your local time zone is, and whether it
observes daylight savings time, some receivers will handle the ST/DST
switch automatically - if you're in one of the countries it's been
programmed for. If any of this works, it's because of software in the
receiver - the GPS system knows nothing about local time.
Of course the system knows nothing about local time. And I'm
pretty sure my 1997-vintage GPS receiver doesn't know anything
about time zone boundaries. It also has no way for me to tell it
the local offset from UTC. But, I took it out in the front yard this
morning and told it to do a cold start. It thought for a while
and then announced that it knew my location, the current UTC time,
and the correct local time (8 hours behind UTC). How did it do that
if the system didn't know how to tell it my time zone offset?
|
It may have a general idea, as far as the US is concerned.
| Quote: |
Now, if I could just rig everything so that my GPS would use
bluetooth to update the microwave, the answering machine, the stove,
the camera, the VCR, etc. What's all this technology for anyway, if it
can't take care of this sort of thing for me? :-)
Yeah, and when the USA changes the dates that DST starts, all this
technology will make the change automatically on the wrong date...
That's why it's a mistake to embed knowledge of DST transition dates in
software or firmware. Just let NTP or the GPS system take care of it.
|
Software and firmware can be updated as required. The GPS
system itself doesn't likely keep tabs on whether a given place is in
one of the hourly, half hourly or the few quarter hourly time zones. I
guess people in e.g. Indiana just have to put up with Windows making
the DST change for the whole state, not just the counties which
observe it.
|
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Guest
|
| Posted:
Wed Nov 02, 2005 3:29 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Sun, 30 Oct 2005 08:41:41 -0800, "Frank ess" <frank@fshe2fs.com>
wrote:
| Quote: | Richard Crowley wrote:
"George" wrote ...
I recently fired up an old analog phone the other day
that did not have a battery attached for at least 4 years
and it got the correct time as soon as it saw the phone
network. I remember every analog phone I had in
the past did the same.
OTOH, my 3-old Panny analog phone (on Cingular)
is currently an hour fast. And my pager (digital, 2-
way) also apparently reqiuires manual intervention.
OyetAnotherH, I don't even know how to _look_ at the hour-of-day on my
cell phone.
|
Doesn't it show by default on the screen when it's not in use? |
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Guest
|
| Posted:
Wed Nov 02, 2005 3:44 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Tue, 01 Nov 2005 03:22:06 -0600, Ron Hunter <rphunter@charter.net>
wrote:
| Quote: | Paul Allen wrote:
George wrote:
ASAAR wrote:
It will no doubt be much smarter. No longer will MS ask "Where do
you want to go today?" Get ready for "Can't get there from here."
and "You are not authorized to go there." As for insanity, this is
from p.11 of the Nov, 2005 issue of Maximum PC discussing DRM:
Agree, most of what I have read about "Vista" seems to indicate that
the biggest new "features" will be all sorts of DRM controls.
I don't expect Microsoft's next version of Windows to affect me much
more than previous versions have. I don't use it unless there's no
other choice, and there's almost always some other choice.
What does bother me is the apparent push to develop DRM-equipped
hardware that can refuse to operate for an OS or application that
cannot authenticate itself. The authentication method is protected
by an expensive license, precluding its use by open-source
software. Magnetic disk makers have floated such schemes, and
now it seems the next generation of optical drives may have
hardware-embedded DRM. There's an awful lot of money pushing
this, and the current US administration is openly hostile to
the rights of consumers. Most past copy protection schemes have
either failed or been abandoned, but the technological means to
restrict your right to the fair use of content are becoming
increasingly cheap and sophisticated.
Paul Allen
All this DRM stuff will have to pass the muster of the marketplace. I
recall a company that 'copy protected' it software disks in such a way
that attempting to copy them rendered both the copy, and original
unreadable. They didn't last long!
HOW does DRM relate to rec.photo.digital, and why cross-post to this NG?
|
For starters, there was a proposal a couple of years ago to
require DRM in all AD converters. It was intended to prevent operation
of all recording devices when protected content was detected, either
audio or video. This would have embedded DRM info in copyrighted
images, so your videocam ould shut down if it scanned past a
copy-prtected Coke sign. It would also shut down if you were recording
your kid's wedding and the DJ fired up a copy-protected piece of
music. Hell, give it a couple of years and the music won't even play
on a device that doesn't have a registered-OK serial number.
In view of that, your digital camera would have been prevented
from taking vacation photos if a protected piece of advertising showed
up in the viewfinder.
If Ben Franklin tried to start the American free public
library system today, he'd be snuffed in court by the **AA. As it is,
they're very much against the idea of libraries lending out their CDs
and DVDs, just haven't bought enough legislators to do so yet. |
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Guest
|
| Posted:
Wed Nov 02, 2005 3:51 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Mon, 31 Oct 2005 15:58:44 -0600, Andrew Rossmann
<andysnewsreply@no_junk.comcast.net> wrote:
| Quote: | One of my 'atomic' clocks didn't adjust until sometime in the evening.
|
Because most of them only correct once a day, not
continuously. |
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ASAAR
Guest
|
| Posted:
Wed Nov 02, 2005 4:35 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Tue, 01 Nov 2005 21:51:48 GMT, kashe@sonic.net wrote:
| Quote: | One of my 'atomic' clocks didn't adjust until sometime in the evening.
Because most of them only correct once a day, not
continuously.
|
Mine checks for a radio update four times daily. As it's a small
battery powered clock I sometimes disable the auto-update feature.
I have an older, stupider line powered clock. After a power failure
it will again get the correct time, but for the wrong time location
since the time zone is stored in volatile memory. |
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lacunae
Guest
|
| Posted:
Wed Nov 02, 2005 5:04 am Post subject:
Re: End of Daylight Time in US: Have you changed your camera |
|
|
On Sun, 30 Oct 2005 02:52:42 -0600, Ron Hunter wrote:
| Quote: | Be glad you don't live in Indiana where the time varies county by county!
|
thought it was only a handful of counties where it varies? (15/92)
most of Indiana stays on EST all year round
the parts near Chicago do CST/CDT (like Chicago does)
and then there are some parts in the southwest that do CST/CDT
and some other parts in the southeast that do EST/EDT
Indiana is supposed to be adopting Daylight Savings Time in 2006 |
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