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Why did my PDA version of Seeyou IGC file fail to be accepted by OLC?
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BG
Mar 27, 2023, 10:08:53 PM3/27/23
to
After too many years to mention, a file I submitted to OLC was not excepted from my ancient version of SeeYou on a PDA? It gave a crazy error message that Oct 2, 2003 was in the log. I might be wrong but I am sure the date and time are gotten from the GPS signal so how can that be?? Maybe my ancient version of Seeyou is now behaving a different way or the GPS signal format has changed recently? Be curious of others have experienced something similar. It was less than a month ago all was OK. I submitted the same flight captured by my Flarm box and all was OK.
Moshe Braner
Mar 27, 2023, 10:29:47 PM3/27/23
to
On 3/27/2023 10:08 PM, BG wrote:
> After too many years to mention, a file I submitted to OLC was not excepted from my ancient version of SeeYou on a PDA? It gave a crazy error message that Oct 2, 2003 was in the log. I might be wrong but I am sure the date and time are gotten from the GPS signal so how can that be?? Maybe my ancient version of Seeyou is now behaving a different way or the GPS signal format has changed recently? Be curious of others have experienced something similar. It was less than a month ago all was OK. I submitted the same flight captured by my Flarm box and all was OK.
>
Sounds like your PDA is so "ancient" that the GPS unit you use with it
> After too many years to mention, a file I submitted to OLC was not excepted from my ancient version of SeeYou on a PDA? It gave a crazy error message that Oct 2, 2003 was in the log. I might be wrong but I am sure the date and time are gotten from the GPS signal so how can that be?? Maybe my ancient version of Seeyou is now behaving a different way or the GPS signal format has changed recently? Be curious of others have experienced something similar. It was less than a month ago all was OK. I submitted the same flight captured by my Flarm box and all was OK.
>
has rolled over the GPS "epoch" (1024 weeks - the time from Oct. 2003
until now). It's a problem with the GPS (or one may say, the design of
the GPS system as a whole), not SeeYou. Your GPS module may or may not
be fixable or replaceable. You can manually edit the date in the header
of the flight log (it's plain text, open it in Wordpad) - but then the
log's "security" will be broken and OLC will punish you with a different
color security icon.
kinsell
Mar 27, 2023, 11:43:09 PM3/27/23
to
On 3/27/23 8:08 PM, BG wrote:> I might be wrong but I am sure the date
the year within an 18.6 year range. Beyond that, receivers had to
determine how many rollovers had occurred since the ssytem went into
operation. They usually did this by a small amount of RAM kept alive
with a tiny rechargeable battery. If the battery ever got discharged,
then the receiver had to be serviced, or sometimes software in the
receiver could be updated to patch the problem.
Since this is the beginning of the season in the top half of the world,
the most likely scenario is that your tiny battery wasn't kept
adequately charged over the winter, and the RAM lost track of how many
rollovers have occurred.
The GPS system has long been upgraded to fix the problem, but old
receivers don't receive the enhanced signals that fix the date problem.
-Dave
and time are gotten from the GPS signal so how can that be??
The original GPS system only transmitted enough information to determine
the year within an 18.6 year range. Beyond that, receivers had to
determine how many rollovers had occurred since the ssytem went into
operation. They usually did this by a small amount of RAM kept alive
with a tiny rechargeable battery. If the battery ever got discharged,
then the receiver had to be serviced, or sometimes software in the
receiver could be updated to patch the problem.
Since this is the beginning of the season in the top half of the world,
the most likely scenario is that your tiny battery wasn't kept
adequately charged over the winter, and the RAM lost track of how many
rollovers have occurred.
The GPS system has long been upgraded to fix the problem, but old
receivers don't receive the enhanced signals that fix the date problem.
-Dave
Tim Newport-Peace
Mar 28, 2023, 4:50:45 AM3/28/23
to
was 12th August 2003 (unless my calculations are wrong). So where does
2nd October 2003 come from?
Dan Marotta
Mar 28, 2023, 11:00:32 AM3/28/23
to
Way back when, the system engineer decided that no electronic device
would EVER need no more than 10 bits for the date field since (he
thought) no electronic device would last longer than that. OR, the
components of the time were not capable of supporting the extra bits to
make the epoch 2048 or 4096 weeks.
Kinda like the Y2K panic back in 1999. I was a systems engineer at
FlightSafety back then and rolled my eyes at the stupidity of those
earlier engineers who made us replace a lot of computer code and
hardware to add one byte to the date field. My wife, a software
engineer at the time, was one of only a couple of passengers on a DC to
Denver flight on 12/31/99. Everyone else thought the world would come
to an end and planes would fall from the sky at the rollover. Kinda
like "atmospheric rivers" we hear about today...
It's different today: I just saw a 1 TB USB stick on Amazon for under $35.
Dan
5J
would EVER need no more than 10 bits for the date field since (he
thought) no electronic device would last longer than that. OR, the
components of the time were not capable of supporting the extra bits to
make the epoch 2048 or 4096 weeks.
Kinda like the Y2K panic back in 1999. I was a systems engineer at
FlightSafety back then and rolled my eyes at the stupidity of those
earlier engineers who made us replace a lot of computer code and
hardware to add one byte to the date field. My wife, a software
engineer at the time, was one of only a couple of passengers on a DC to
Denver flight on 12/31/99. Everyone else thought the world would come
to an end and planes would fall from the sky at the rollover. Kinda
like "atmospheric rivers" we hear about today...
It's different today: I just saw a 1 TB USB stick on Amazon for under $35.
Dan
5J
kinsell
Mar 28, 2023, 9:50:42 PM3/28/23
to
On 3/28/23 9:00 AM, Dan Marotta wrote:
> Way back when, the system engineer decided that no electronic device
> would EVER need no more than 10 bits for the date field since (he
> thought) no electronic device would last longer than that. OR, the
> components of the time were not capable of supporting the extra bits to
> make the epoch 2048 or 4096 weeks.
>
> Kinda like the Y2K panic back in 1999. I was a systems engineer at
> FlightSafety back then and rolled my eyes at the stupidity of those
> earlier engineers who made us replace a lot of computer code and
> hardware to add one byte to the date field. My wife, a software
> engineer at the time, was one of only a couple of passengers on a DC to
> Denver flight on 12/31/99. Everyone else thought the world would come
> to an end and planes would fall from the sky at the rollover. Kinda
> like "atmospheric rivers" we hear about today...
>
> It's different today: I just saw a 1 TB USB stick on Amazon for under $35.
Many of those super deals are phony, they take a small memory stick and
> Way back when, the system engineer decided that no electronic device
> would EVER need no more than 10 bits for the date field since (he
> thought) no electronic device would last longer than that. OR, the
> components of the time were not capable of supporting the extra bits to
> make the epoch 2048 or 4096 weeks.
>
> Kinda like the Y2K panic back in 1999. I was a systems engineer at
> FlightSafety back then and rolled my eyes at the stupidity of those
> earlier engineers who made us replace a lot of computer code and
> hardware to add one byte to the date field. My wife, a software
> engineer at the time, was one of only a couple of passengers on a DC to
> Denver flight on 12/31/99. Everyone else thought the world would come
> to an end and planes would fall from the sky at the rollover. Kinda
> like "atmospheric rivers" we hear about today...
>
> It's different today: I just saw a 1 TB USB stick on Amazon for under $35.
set it to report a much larger capacity. Just saw a TB stick advertised
for $20, it apparently is only 64 GB, it's USB2.0 instead of 3.0
advertised, and BTW, has a virus preloaded.
Date problems haven't all been fixed, some older Unix systems and
derivatives will start reporting 1910 as the date in 2038 due to some
integer hitting 2.1 billion seconds (2^31).
Dan Marotta
Mar 29, 2023, 12:17:43 PM3/29/23
to
Ain't that (2^32)-1 or 4.3 billion? In any case, my flying then, if at
all, will probably be limited to the carnival ride... Hope not!
Dan
5J
all, will probably be limited to the carnival ride... Hope not!
Dan
5J
kinsell
Mar 29, 2023, 1:42:01 PM3/29/23
to
Nope, 2^31, they used a signed integer.
Reminds me of when I was doing disk testing for a major US electronics
company, we were debating whether the file system was going to break at
2 GB or 4 GB. So I bought a huge disk (for the time), and found it
broke at 1 GB. Who could have ever guessed we'd have disks bigger than
a gigabyte someday?
Reminds me of when I was doing disk testing for a major US electronics
company, we were debating whether the file system was going to break at
2 GB or 4 GB. So I bought a huge disk (for the time), and found it
broke at 1 GB. Who could have ever guessed we'd have disks bigger than
a gigabyte someday?
Mark Mocho
Mar 29, 2023, 2:04:10 PM3/29/23
to
I remember working with an NCR 8230, a "mini" computer that was the size of a refrigerator. Had two 5 MB hard drive disks that were 14 inches in diameter.
Martin Gregorie
Mar 29, 2023, 3:45:56 PM3/29/23
to
On Wed, 29 Mar 2023 10:17:38 -0600, Dan Marotta wrote:
> Ain't that (2^32)-1 or 4.3 billion? In any case, my flying then, if at
> all, will probably be limited to the carnival ride... Hope not!
>
A lot of the Y2K problems (i.e. GPS as well as *NIX [and Windoze ?]) can
> Ain't that (2^32)-1 or 4.3 billion? In any case, my flying then, if at
> all, will probably be limited to the carnival ride... Hope not!
>
be blamed on whoever thought it would be a good idea to shoehorn both date
and time of day into a single integer variable.
Back in the day, before micro- or minicomputers existed, most systems kept
the current date and time in two separate variables, so for instance, in
an ICL 1900, which used 24 bit words with date zero defined as 31 December
1899, you wouldn't have hit its Y2K moment until some time in September
24865 AD. I'd guess the same applies to Big Blue's boxen too or COBOL
wouldn't have defined DATE and TIME as two separate system variables.
--
Martin | martin at
Gregorie | gregorie dot org
kinsell
Mar 29, 2023, 6:39:15 PM3/29/23
to
transmitted by the satellite, compounded by makers of receivers who
thought storing a few more bits in static RAM, powered by a tiny
battery, was adequate to address the situation. Once the battery gets
discharged, no amount of recharging fixes it. No provision is made to
let the user set the bits back to what they ought to be.
Bugs like this have been around forever, in 2004 a subsidiary of Delta
had their crew scheduling system crash at Christmas because it could
only handle 2^15 crew changes in a month.
https://www.theregister.com/2004/12/30/comair_bad_box/
Why they used a signed integer there is hard to guess. These problems
are hard to test for, but most of them are easy to predict if only the
programmers would take the time to do simple calculations. Southwest
had a similar crew scheduling meltdown this last Christmas with bad
software. The Aussies are smart, they moved Christmas to the middle of
summer, so this wouldn't happen :-)
Even Great Britain is not immune, they used 1987 era software to track
Covid cases, with predictable results:
https://www.bbc.com/news/technology-54423988
Martin Gregorie
Mar 29, 2023, 8:21:15 PM3/29/23
to
On Wed, 29 Mar 2023 16:39:09 -0600, kinsell wrote:
> Yep. The GPS debacle was caused by limited bits of information
> transmitted by the satellite, compounded by makers of receivers who
> thought storing a few more bits in static RAM, powered by a tiny
> battery, was adequate to address the situation. Once the battery gets
> discharged, no amount of recharging fixes it. No provision is made to
> let the user set the bits back to what they ought to be.
>
You may be amused to hear that I still have a usable pair of Garmin GPS 2+
> Yep. The GPS debacle was caused by limited bits of information
> transmitted by the satellite, compounded by makers of receivers who
> thought storing a few more bits in static RAM, powered by a tiny
> battery, was adequate to address the situation. Once the battery gets
> discharged, no amount of recharging fixes it. No provision is made to
> let the user set the bits back to what they ought to be.
>
handheld units, which I used first for Free Flight model retrieval and
then, when I started to fly XC in my club's Pegase 90 they got used for
navigation and to drive my first logger, which was just a recorder and
needed an external GPS.
So, while they *might* possibly be useful one day, they're really just old
age pensioners. When outdoors and in use, they run on a set of four AA
cells.
Mine are still viable because every few months I fire them up to see if
there is still usable life in the AA cells, replace them if they're low,
and sometimes take the GPS units outside to see if they can still get a
fix. So far, they're still working well. Used this way, a set of AA cells
lasts for over a year.
The GPS 2+ units have a small, internal non-replaceable disk battery to
keep their internal RAM alive while their main batteries are replaced, so
as long as this battery is good and their AA cells are replaced before
they go flat, they remember which GPS epoch they are in and will continue
to get a valid fix and show the right time when taken outside and fired
up.
> Bugs like this have been around forever, in 2004 a subsidiary of Delta
> had their crew scheduling system crash at Christmas because it could
> only handle 2^15 crew changes in a month.
>
> https://www.theregister.com/2004/12/30/comair_bad_box/
>
> Why they used a signed integer there is hard to guess.
>
of C designers and programmers would just specify an int rather than an
unsigned int without thinking, but in any case, using an unsigned int only
doubles the time to crash, IMO that sort of mistake would be less likely
if the system was written in COBOL, Java or PL/1 because of the syntax
used to declare numeric variables, but that fairly irrelevant because not
checking for overflow on a variable that is used as a key or index value
is just plain careless.
But to my mind its even odder that they would have used such a short
integer. Given that the IBM AIX systems they were using at the time were
32 or 64 bit systems, the fact is that the flight crew scheduling software
crashed due to integer overflow on a signed 15 bit integer!
That would tend to show the crash was a software error pure and simple.
> These problems
> are hard to test for, but most of them are easy to predict if only the
> programmers would take the time to do simple calculations. Southwest
> had a similar crew scheduling meltdown this last Christmas with bad
> software. The Aussies are smart, they moved Christmas to the middle of
> summer, so this wouldn't happen :-)
>
> Even Great Britain is not immune, they used 1987 era software to track
> Covid cases, with predictable results:
>
>
> https://www.bbc.com/news/technology-54423988
An interesting read. Thanks for posting.it.
kinsell
Mar 29, 2023, 10:54:43 PM3/29/23
to
Doesn't surprise me at all. I've still got a Garmin GPS 12, one of the
first units targeted at backpackers. Used it for many years for glider
navigation, now it's relegated as a backup device in case ship power
fails. Which it hasn't in 40 years of flying. The date for the 12 is
still correct, not that it matters for its current use.
The little rechargeable battery built in works great in that
application, since it's charged by the other batteries continuously.
However, take that same circuitry, build it into a certified logger that
is not likely to get powered up over the winter season (and which
requires correct time), and you end up with the current situation, a
slow but steady trickle of loggers going belly up as time marches on.
-Dave
first units targeted at backpackers. Used it for many years for glider
navigation, now it's relegated as a backup device in case ship power
fails. Which it hasn't in 40 years of flying. The date for the 12 is
still correct, not that it matters for its current use.
The little rechargeable battery built in works great in that
application, since it's charged by the other batteries continuously.
However, take that same circuitry, build it into a certified logger that
is not likely to get powered up over the winter season (and which
requires correct time), and you end up with the current situation, a
slow but steady trickle of loggers going belly up as time marches on.
-Dave
Francois HERSEN
Mar 30, 2023, 6:04:57 AM3/30/23
to
Dan Marotta
Mar 30, 2023, 11:52:58 AM3/30/23
to
Will good AA batteries keep the thing alive while a soldering guru
replaces the disk battery? If not, will it come back to life with a new
"keep alive" battery installed? The battery in the Garmin 396 in my
Stemme was dead and Garmin wanted $400 to replace the $3 internal
battery. I bought one at the grocery store and installed it myself.
Works fine.
Garmin also told my wife that the internal battery in her portable car
GPS could not be replaced and that she should buy a new unit. She found
a battery online and I replaced it for her. Then she bought a new car
with a built-in GPS... We keep the portable to use in airport crew cars
when we make trips in our airplane.
Dan
5J
replaces the disk battery? If not, will it come back to life with a new
"keep alive" battery installed? The battery in the Garmin 396 in my
Stemme was dead and Garmin wanted $400 to replace the $3 internal
battery. I bought one at the grocery store and installed it myself.
Works fine.
Garmin also told my wife that the internal battery in her portable car
GPS could not be replaced and that she should buy a new unit. She found
a battery online and I replaced it for her. Then she bought a new car
with a built-in GPS... We keep the portable to use in airport crew cars
when we make trips in our airplane.
Dan
5J
Dan Marotta
Mar 30, 2023, 11:54:38 AM3/30/23
to
I've got a Trimble Flight Mate Pro in the hangar. Wonder if it will
lock on with a new set of AA batteries...
Dan
5J
lock on with a new set of AA batteries...
Dan
5J
kinsell
Mar 30, 2023, 12:17:00 PM3/30/23
to
The tiny battery powers a real time clock circuit, so the GPS has a good
idea where the satellites are and can lock on faster.
If the battery has been discharged, you lose the correct year. I think
the GPS can still get a lock, but it may take a lot longer. Unless you
left the AA batteries in too long, and they've corroded the contacts.
The problem with secure flight recorders is the tiny battery is
protected with an electronic seal, so accessing the battery breaks the
seal and must be resealed by someone authorized by the factory.
For example, the CAI302 recorder used a standard Garmin GPS15 module,
they're still available at reasonable prices, but you can't just open up
the unit and replace it yourself, and still have a good security seal.
-Dave
idea where the satellites are and can lock on faster.
If the battery has been discharged, you lose the correct year. I think
the GPS can still get a lock, but it may take a lot longer. Unless you
left the AA batteries in too long, and they've corroded the contacts.
The problem with secure flight recorders is the tiny battery is
protected with an electronic seal, so accessing the battery breaks the
seal and must be resealed by someone authorized by the factory.
For example, the CAI302 recorder used a standard Garmin GPS15 module,
they're still available at reasonable prices, but you can't just open up
the unit and replace it yourself, and still have a good security seal.
-Dave
Martin Gregorie
Mar 30, 2023, 1:07:50 PM3/30/23
to
On Thu, 30 Mar 2023 09:52:51 -0600, Dan Marotta wrote:
> Will good AA batteries keep the thing alive while a soldering guru
> replaces the disk battery?
>
My original Garmin GPS 2+ got left a bit too long with either no or dead
> Will good AA batteries keep the thing alive while a soldering guru
> replaces the disk battery?
>
AA cells (I forget which: it was back in the late '90s) Garmin replaced
the tiny coin cell as a freebie and said that I'd just squeaked in before
support for that model was dropped.
I never found out whether the GPS 2+ was capable in recovering the epoch
and year if left running for long enough, or whether the coin cell
replacement process also included setting the correct epoch and year.
I've never seen anydescriptions of how GPS receivers recognise the start
of a new epoch and what internal variables they need to update when they
get it.
> If not, will it come back to life with a new "keep alive" battery
> installed?
GPS receiver recent enough to use EEPROM rather than battery backed RAM to
store data thats retained when its powered off is pretty much guaranteed
to work correctly unless its been physically damaged.
Tim Newport-Peace
Mar 30, 2023, 3:44:02 PM3/30/23
to
On 30/03/2023 18:07, Martin Gregorie wrote:
> On Thu, 30 Mar 2023 09:52:51 -0600, Dan Marotta wrote:
>
>> Will good AA batteries keep the thing alive while a soldering guru
>> replaces the disk battery?
>>
> My original Garmin GPS 2+ got left a bit too long with either no or dead
> AA cells (I forget which: it was back in the late '90s) Garmin replaced
> the tiny coin cell as a freebie and said that I'd just squeaked in before
> support for that model was dropped.
>
> I never found out whether the GPS 2+ was capable in recovering the epoch
> and year if left running for long enough, or whether the coin cell
> replacement process also included setting the correct epoch and year.
>
> I've never seen any descriptions of how GPS receivers recognise the start
> On Thu, 30 Mar 2023 09:52:51 -0600, Dan Marotta wrote:
>
>> Will good AA batteries keep the thing alive while a soldering guru
>> replaces the disk battery?
>>
> My original Garmin GPS 2+ got left a bit too long with either no or dead
> AA cells (I forget which: it was back in the late '90s) Garmin replaced
> the tiny coin cell as a freebie and said that I'd just squeaked in before
> support for that model was dropped.
>
> I never found out whether the GPS 2+ was capable in recovering the epoch
> and year if left running for long enough, or whether the coin cell
> replacement process also included setting the correct epoch and year.
>
> of a new epoch and what internal variables they need to update when they
> get it.
As part of the data stream, it receives a week number. When this clicks
> get it.
from 1023 to 0, it is a new epoch. It does not receive the epoch number,
which is a problem, so success/failure depends on if the epoch number is
stored in volatile or non-volatile memory.
>
>
>> If not, will it come back to life with a new "keep alive" battery
>> installed?
As above.
>
>> If not, will it come back to life with a new "keep alive" battery
>> installed?
>
> My guess that depends on the make and model of GPS. All I know is that any
kinsell
Mar 31, 2023, 1:24:31 AM3/31/23
to
On 3/30/23 1:44 PM, Tim Newport-Peace wrote:
> On 30/03/2023 18:07, Martin Gregorie wrote:
>> On Thu, 30 Mar 2023 09:52:51 -0600, Dan Marotta wrote:
>>
>>> Will good AA batteries keep the thing alive while a soldering guru
>>> replaces the disk battery?
>>>
>> My original Garmin GPS 2+ got left a bit too long with either no or dead
>> AA cells (I forget which: it was back in the late '90s) Garmin replaced
>> the tiny coin cell as a freebie and said that I'd just squeaked in before
>> support for that model was dropped.
>>
>> I never found out whether the GPS 2+ was capable in recovering the epoch
>> and year if left running for long enough, or whether the coin cell
>> replacement process also included setting the correct epoch and year.
>>
>> I've never seen any descriptions of how GPS receivers recognise the start
>> of a new epoch and what internal variables they need to update when they
>> get it.
> As part of the data stream, it receives a week number. When this clicks
> from 1023 to 0, it is a new epoch. It does not receive the epoch number,
> which is a problem, so success/failure depends on if the epoch number is
> stored in volatile or non-volatile memory.
Since 2014, the birds have added a new signal with a 13 bit week number
> On 30/03/2023 18:07, Martin Gregorie wrote:
>> On Thu, 30 Mar 2023 09:52:51 -0600, Dan Marotta wrote:
>>
>>> Will good AA batteries keep the thing alive while a soldering guru
>>> replaces the disk battery?
>>>
>> My original Garmin GPS 2+ got left a bit too long with either no or dead
>> AA cells (I forget which: it was back in the late '90s) Garmin replaced
>> the tiny coin cell as a freebie and said that I'd just squeaked in before
>> support for that model was dropped.
>>
>> I never found out whether the GPS 2+ was capable in recovering the epoch
>> and year if left running for long enough, or whether the coin cell
>> replacement process also included setting the correct epoch and year.
>>
>> I've never seen any descriptions of how GPS receivers recognise the start
>> of a new epoch and what internal variables they need to update when they
>> get it.
> As part of the data stream, it receives a week number. When this clicks
> from 1023 to 0, it is a new epoch. It does not receive the epoch number,
> which is a problem, so success/failure depends on if the epoch number is
> stored in volatile or non-volatile memory.
instead of 10, so the epocs are 8 times bigger (about 158 years). It's
unlikely receivers that can handle the new information have made their
way into data loggers used by glider pilots.
Power Flarm, LXNav, and ClearNav seem to favor U-box gps modules, which
require a tiny amount of power for a real time clock if you want a fast
lock.
U-blox is just using firmware to provide 19.6 years of trouble-free
operation after the date the firmware was created:
https://content.u-blox.com/sites/default/files/u-blox-GPS-WeekNumberRolloverWorkaround_IN_%28UBX-19039990%29.pdf
No magic there.
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