«

On Wed, 22 Dec 2010 18:44:19 -0600, Peabody wrote:

> A friend of mine has a new Canon T2i, and is having trouble with
> corrupted files when he removes the SD card from the camera and uses a
> card reader to transfer the jpegs to his computer.
>
> When the card is in the camera, everything works fine. All the pics
> display fine in playback mode, and in fact he can transfer the pics just
> fine by connecting a USB cable directly to the camera.
>
> I've tried transferring the files to my computer using his card reader,
> and there are no problems. But using my hex editor, I've compared the
> good and bad versions of a few of the files that were corrupted, and the
> bad versions are different by 512 bytes - that segment of the bad file
> contains a copy of a previously transferred 512 bytes in the file,
> rather than what should be there. For example, at 24ca00-24cbff one
> file has a copy of the contents at 24c400-24c5ff rather than what is in
> the good file at 24ca00. But the absolute and relative addresses
> involved are not the same from one corrupted file to another. And some
> files have multiple 512-byte screwups. And of course many of the files
> aren't corrupt at all.
>
> Since I've confirmed he didn't imagine this, but since I also can't
> duplicate it, I'm trying to make sure I've considered all the
> possiblitites for the cause. Since the files are correct on the SD
> card, I would conclude it's highly unlikely the camera is at fault. I
> think it's also unlikely, but maybe not highly unlikely, that there's a
> problem with the card. While he reports that he has had the problem
> with two Transcend class 6 cards, but not with a Lexar card, all of
> those cards work fine using his card reader on my computer.
>
> The card reader could be at fault, even though it works fine for me. But
> I'm leaning more toward a USB problem - either a bad cable (he didn't
> bring me the cable he's been using with the reader), or possibly not
> enough current available at the port he's connecting to.
>
> Is there any other possiblity I haven't considered that he should check
> for? His computer works fine, and there's no indication of any other
> file corruption issues.

It could be a USB issue - that could be related to a corrupt driver or an
OS problem. Assuming he routinely uses MS, I'd suggest booting a Live
Linux CD and see if the problem persists. If so, then it's most likely
hardware - if not then it would certainly indicate software on the MS
side.


>
> Thanks for any suggestions.
>
> By the way, I gotta tell you this T2i is one slick mother. The high-ISO
> performance is very impressive.

In article <>, ray <>
wrote:

> On Wed, 22 Dec 2010 18:44:19 -0600, Peabody wrote:
>
> > A friend of mine has a new Canon T2i, and is having trouble with
> > corrupted files when he removes the SD card from the camera and uses a
> > card reader to transfer the jpegs to his computer.
> >
> > When the card is in the camera, everything works fine. All the pics
> > display fine in playback mode, and in fact he can transfer the pics just
> > fine by connecting a USB cable directly to the camera.
> >
> > I've tried transferring the files to my computer using his card reader,
> > and there are no problems. But using my hex editor, I've compared the
> > good and bad versions of a few of the files that were corrupted, and the
> > bad versions are different by 512 bytes - that segment of the bad file
> > contains a copy of a previously transferred 512 bytes in the file,
> > rather than what should be there. For example, at 24ca00-24cbff one
> > file has a copy of the contents at 24c400-24c5ff rather than what is in
> > the good file at 24ca00. But the absolute and relative addresses
> > involved are not the same from one corrupted file to another. And some
> > files have multiple 512-byte screwups. And of course many of the files
> > aren't corrupt at all.
> >
> > Since I've confirmed he didn't imagine this, but since I also can't
> > duplicate it, I'm trying to make sure I've considered all the
> > possiblitites for the cause. Since the files are correct on the SD
> > card, I would conclude it's highly unlikely the camera is at fault. I
> > think it's also unlikely, but maybe not highly unlikely, that there's a
> > problem with the card. While he reports that he has had the problem
> > with two Transcend class 6 cards, but not with a Lexar card, all of
> > those cards work fine using his card reader on my computer.
> >
> > The card reader could be at fault, even though it works fine for me. But
> > I'm leaning more toward a USB problem - either a bad cable (he didn't
> > bring me the cable he's been using with the reader), or possibly not
> > enough current available at the port he's connecting to.
> >
> > Is there any other possiblity I haven't considered that he should check
> > for? His computer works fine, and there's no indication of any other
> > file corruption issues.
>
> It could be a USB issue - that could be related to a corrupt driver or an
> OS problem. Assuming he routinely uses MS, I'd suggest booting a Live
> Linux CD and see if the problem persists. If so, then it's most likely
> hardware - if not then it would certainly indicate software on the MS
> side.
>
>
> >
> > Thanks for any suggestions.
> >
> > By the way, I gotta tell you this T2i is one slick mother. The high-ISO
> > performance is very impressive.

Card readers are so cheap that I tend to buy them by the handful so that
when (not if) they go bad I can throw them out and reach for the next
one. Buying different brands seems to spread the risk a bit.

Cards themselves go bad, and when they do, they go very bad. If it were
me (and it was last week and also three weeks ago) I'd start over with a
new card and a new reader, tossing the suspect ones.

In my experience cards are better-made than readers. But as soon as
there is a sign of impending failure I don't hesitate to cut the card in
half, cut the cord from the reader, and throw out the entire mess. Flash
memory goes bad in a non-linear fashion. It is not an archival medium,
and was never meant for long-term storage.

Just my two cents.

On 12/22/2010 9:30 PM, shiva das wrote:
> In article<>, ray<>
> wrote:
>
>> On Wed, 22 Dec 2010 18:44:19 -0600, Peabody wrote:
>>
>>> A friend of mine has a new Canon T2i, and is having trouble with
>>> corrupted files when he removes the SD card from the camera and uses a
>>> card reader to transfer the jpegs to his computer.
>>>
>>> When the card is in the camera, everything works fine. All the pics
>>> display fine in playback mode, and in fact he can transfer the pics just
>>> fine by connecting a USB cable directly to the camera.
>>>
>>> I've tried transferring the files to my computer using his card reader,
>>> and there are no problems. But using my hex editor, I've compared the
>>> good and bad versions of a few of the files that were corrupted, and the
>>> bad versions are different by 512 bytes - that segment of the bad file
>>> contains a copy of a previously transferred 512 bytes in the file,
>>> rather than what should be there. For example, at 24ca00-24cbff one
>>> file has a copy of the contents at 24c400-24c5ff rather than what is in
>>> the good file at 24ca00. But the absolute and relative addresses
>>> involved are not the same from one corrupted file to another. And some
>>> files have multiple 512-byte screwups. And of course many of the files
>>> aren't corrupt at all.
>>>
>>> Since I've confirmed he didn't imagine this, but since I also can't
>>> duplicate it, I'm trying to make sure I've considered all the
>>> possiblitites for the cause. Since the files are correct on the SD
>>> card, I would conclude it's highly unlikely the camera is at fault. I
>>> think it's also unlikely, but maybe not highly unlikely, that there's a
>>> problem with the card. While he reports that he has had the problem
>>> with two Transcend class 6 cards, but not with a Lexar card, all of
>>> those cards work fine using his card reader on my computer.
>>>
>>> The card reader could be at fault, even though it works fine for me. But
>>> I'm leaning more toward a USB problem - either a bad cable (he didn't
>>> bring me the cable he's been using with the reader), or possibly not
>>> enough current available at the port he's connecting to.
>>>
>>> Is there any other possiblity I haven't considered that he should check
>>> for? His computer works fine, and there's no indication of any other
>>> file corruption issues.
>>
>> It could be a USB issue - that could be related to a corrupt driver or an
>> OS problem. Assuming he routinely uses MS, I'd suggest booting a Live
>> Linux CD and see if the problem persists. If so, then it's most likely
>> hardware - if not then it would certainly indicate software on the MS
>> side.
>>
>>
>>>
>>> Thanks for any suggestions.
>>>
>>> By the way, I gotta tell you this T2i is one slick mother. The high-ISO
>>> performance is very impressive.
>
> Card readers are so cheap that I tend to buy them by the handful so that
> when (not if) they go bad I can throw them out and reach for the next
> one. Buying different brands seems to spread the risk a bit.
>
> Cards themselves go bad, and when they do, they go very bad. If it were
> me (and it was last week and also three weeks ago) I'd start over with a
> new card and a new reader, tossing the suspect ones.
>
> In my experience cards are better-made than readers. But as soon as
> there is a sign of impending failure I don't hesitate to cut the card in
> half, cut the cord from the reader, and throw out the entire mess. Flash
> memory goes bad in a non-linear fashion. It is not an archival medium,
> and was never meant for long-term storage.
>
> Just my two cents.

Which is exactly when I download every day. If something goes bad, I
only lose that day.

--
Peter

On Wed, 22 Dec 2010 21:30:31 -0500, shiva das wrote:

> In article <>, ray <>
> wrote:
>
>> On Wed, 22 Dec 2010 18:44:19 -0600, Peabody wrote:
>>
>> > A friend of mine has a new Canon T2i, and is having trouble with
>> > corrupted files when he removes the SD card from the camera and uses
>> > a card reader to transfer the jpegs to his computer.
>> >
>> > When the card is in the camera, everything works fine. All the pics
>> > display fine in playback mode, and in fact he can transfer the pics
>> > just fine by connecting a USB cable directly to the camera.
>> >
>> > I've tried transferring the files to my computer using his card
>> > reader, and there are no problems. But using my hex editor, I've
>> > compared the good and bad versions of a few of the files that were
>> > corrupted, and the bad versions are different by 512 bytes - that
>> > segment of the bad file contains a copy of a previously transferred
>> > 512 bytes in the file, rather than what should be there. For
>> > example, at 24ca00-24cbff one file has a copy of the contents at
>> > 24c400-24c5ff rather than what is in the good file at 24ca00. But
>> > the absolute and relative addresses involved are not the same from
>> > one corrupted file to another. And some files have multiple 512-byte
>> > screwups. And of course many of the files aren't corrupt at all.
>> >
>> > Since I've confirmed he didn't imagine this, but since I also can't
>> > duplicate it, I'm trying to make sure I've considered all the
>> > possiblitites for the cause. Since the files are correct on the SD
>> > card, I would conclude it's highly unlikely the camera is at fault. I
>> > think it's also unlikely, but maybe not highly unlikely, that there's
>> > a problem with the card. While he reports that he has had the
>> > problem with two Transcend class 6 cards, but not with a Lexar card,
>> > all of those cards work fine using his card reader on my computer.
>> >
>> > The card reader could be at fault, even though it works fine for me.
>> > But I'm leaning more toward a USB problem - either a bad cable (he
>> > didn't bring me the cable he's been using with the reader), or
>> > possibly not enough current available at the port he's connecting to.
>> >
>> > Is there any other possiblity I haven't considered that he should
>> > check for? His computer works fine, and there's no indication of
>> > any other file corruption issues.
>>
>> It could be a USB issue - that could be related to a corrupt driver or
>> an OS problem. Assuming he routinely uses MS, I'd suggest booting a
>> Live Linux CD and see if the problem persists. If so, then it's most
>> likely hardware - if not then it would certainly indicate software on
>> the MS side.
>>
>>
>>
>> > Thanks for any suggestions.
>> >
>> > By the way, I gotta tell you this T2i is one slick mother. The
>> > high-ISO performance is very impressive.
>
> Card readers are so cheap that I tend to buy them by the handful so that
> when (not if) they go bad I can throw them out and reach for the next
> one. Buying different brands seems to spread the risk a bit.

That's fine - and the reader may or may not be the problem here - I've
never had one go bad in 15 years. You may also note, if you actually read
the original post, that the author was able to transfer using his
friend's card reader - without problem - so that most likely is not the
issue.

>
> Cards themselves go bad, and when they do, they go very bad. If it were
> me (and it was last week and also three weeks ago) I'd start over with a
> new card and a new reader, tossing the suspect ones.
>
> In my experience cards are better-made than readers. But as soon as
> there is a sign of impending failure I don't hesitate to cut the card in
> half, cut the cord from the reader, and throw out the entire mess. Flash
> memory goes bad in a non-linear fashion. It is not an archival medium,
> and was never meant for long-term storage.
>
> Just my two cents.

Again, the author indicates that switching the reader and card to another
computer there were no problems - definitely indicates a problem with
that particular system. I offered a way to identify whether it is most
likely hardware or software. Believe it or not, USB cards can go bad and
MS OS's can indeed be corrupted.

On 12/22/2010 11:10 PM, ray wrote:
> On Wed, 22 Dec 2010 21:30:31 -0500, shiva das wrote:
>
>> In article<>, ray<>
>> wrote:
>>
>>> On Wed, 22 Dec 2010 18:44:19 -0600, Peabody wrote:
>>>
>>>> A friend of mine has a new Canon T2i, and is having trouble with
>>>> corrupted files when he removes the SD card from the camera and uses
>>>> a card reader to transfer the jpegs to his computer.
>>>>
>>>> When the card is in the camera, everything works fine. All the pics
>>>> display fine in playback mode, and in fact he can transfer the pics
>>>> just fine by connecting a USB cable directly to the camera.
>>>>
>>>> I've tried transferring the files to my computer using his card
>>>> reader, and there are no problems. But using my hex editor, I've
>>>> compared the good and bad versions of a few of the files that were
>>>> corrupted, and the bad versions are different by 512 bytes - that
>>>> segment of the bad file contains a copy of a previously transferred
>>>> 512 bytes in the file, rather than what should be there. For
>>>> example, at 24ca00-24cbff one file has a copy of the contents at
>>>> 24c400-24c5ff rather than what is in the good file at 24ca00. But
>>>> the absolute and relative addresses involved are not the same from
>>>> one corrupted file to another. And some files have multiple 512-byte
>>>> screwups. And of course many of the files aren't corrupt at all.
>>>>
>>>> Since I've confirmed he didn't imagine this, but since I also can't
>>>> duplicate it, I'm trying to make sure I've considered all the
>>>> possiblitites for the cause. Since the files are correct on the SD
>>>> card, I would conclude it's highly unlikely the camera is at fault. I
>>>> think it's also unlikely, but maybe not highly unlikely, that there's
>>>> a problem with the card. While he reports that he has had the
>>>> problem with two Transcend class 6 cards, but not with a Lexar card,
>>>> all of those cards work fine using his card reader on my computer.
>>>>
>>>> The card reader could be at fault, even though it works fine for me.
>>>> But I'm leaning more toward a USB problem - either a bad cable (he
>>>> didn't bring me the cable he's been using with the reader), or
>>>> possibly not enough current available at the port he's connecting to.
>>>>
>>>> Is there any other possiblity I haven't considered that he should
>>>> check for? His computer works fine, and there's no indication of
>>>> any other file corruption issues.
>>>
>>> It could be a USB issue - that could be related to a corrupt driver or
>>> an OS problem. Assuming he routinely uses MS, I'd suggest booting a
>>> Live Linux CD and see if the problem persists. If so, then it's most
>>> likely hardware - if not then it would certainly indicate software on
>>> the MS side.
>>>
>>>
>>>
>>>> Thanks for any suggestions.
>>>>
>>>> By the way, I gotta tell you this T2i is one slick mother. The
>>>> high-ISO performance is very impressive.
>>
>> Card readers are so cheap that I tend to buy them by the handful so that
>> when (not if) they go bad I can throw them out and reach for the next
>> one. Buying different brands seems to spread the risk a bit.
>
> That's fine - and the reader may or may not be the problem here - I've
> never had one go bad in 15 years. You may also note, if you actually read
> the original post, that the author was able to transfer using his
> friend's card reader - without problem - so that most likely is not the
> issue.
>

If you don't use them, they last many years.


--
Peter