I'm a little confused. I should think it would set or unset the archive
bits for paired raw and JPEGs simultaneously unless only one or the
other were selectively downloaded. But if it appears to work properly
who am I to argue. Mystery solved in any case.
Chuck Norcutt
On 10/4/2010 5:06 PM, Moose wrote:
> On 10/4/2010 12:58 PM, Chuck Norcutt wrote:
>> ...
>>
>> Anyhow, your statement that the downloader did know the files had already
>> been downloaded caused me to think a bit harder. I haven't had to think
>> about internal FAT file structures since about 1987 but I just
>> realized how the downloader must work in order to recognize that the file
>> has already been downloaded. I had completely forgotten about the "archive
>> bit" in the FAT file system. Each file has one byte available
>> for file attributes and one of the bits is called the archive bit. I looked
>> up this tidbit to refresh my memory.
>
> Got it in one. I'd just taken a few shots when I came in and read this post.
> Looking at the CF card, it's clear you are
> right. For other reasons, I've been shooting RAW+the smallest pixel size
> JPEGs. All of today's' images have the archive
> bit set. Prior day's images have it unset on the JPGs, but not the CR2s. I
> suppose ZB uses the JPGs as the key when both
> are shot?
>
> Just erased a couple of the new JPGs on the card, for shots that didn't work,
> then downloaded using ZB. This time, it
> unset all the CR2 file archive bits and left the JPGs set. It's internal
> logic is odd, but to the user, it just works.
>
> This leaves open the question of that the .ctg files may be. A quick search
> unearths:
> -----------------------------------------------
> CTG file extension - Canon Digital Camera Catalog File
>
> CTG files are found on Canon digital camera memory cards and operate as data
> indexes for the image folders stored on the
> memory card. The indexed information is changed as the pictures that the
> information references are removed from the
> camera; the CTG file is removed completely when the folder containing the
> pictures is removed.
>
> These files are proprietary and the information that they store is not known
> ...
> -----------------------------------------------
> It appears that ctg files only appear when the camera creates more than one
> image folder on a card.
>
> Moose
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