Well, y'all may be surprised some day. The problem with deleting from
the computer is that the computer has no knowledge of the internal
structure of files and folders that the camera creates and requires.
When you delete from the computer it deletes files from the currently
open folder. The problem is there may be files in other folders that
are not active. The camera allows you to create your own folders and,
in addition, when the camera runs out of image numbers in the sequence
it will create another folder on its own. That's to prevent having
duplicate image numbers (file names) in the same folder. You also need
to make sure your downloading software recognizes additional file
folders... especially the one the camera created on max image number
rollover that you probably had no knowledge of.
In addition, a file delete doesn't actually delete anything. It just
marks the name as deleted. That directory space and the space that
directory entry points to will not be reused until the previously unused
space is filled up. This will cause the write time to be a little bit
slower since it's forced to search farther (sequentially) through the
directory to find available space.
Finally, if selective deletion is done (with the exception of E-1 raw
files which are all the same size) you end up with storage
fragmentation. This slows performance but is not nearly as bad on a
flash card as on a physical disk. However, should you accidentally
delete something you didn't intend to, or, if you accidentally formatted
the card, you would not be able to get complete recovery with a disk of
flash card recovery utility due to the fragmentation. The recovery
software will not be able to figure out which pieces of image data go
together since they're not sequentially located.
Those of you who have been deleting files from your CF cards for a long
time may never have a problem. However should you ever have the need to
try recovery software you may be sadly disappointed.
My recommendation for using flash memory cards is to
1) label them. (mine are 2A, 2B, 2C, 8A, 8B, 8C for capacity, sequence)
2) rotate usage in some sequence
3) don't format or delete anything until necessary
4) check the next card to be used to be sure the content is old
5) format *in camera* to clear the directory (while verifying that
it's all writeable) and refresh file folders the camera depends on
6) periodically, format the card in the computer being sure *not* to
choose "Quick Format". If you do a full format it will write to
and verify all storage locations on the card. Then do a format in
camera to restore the camera's file structures.
Chuck Norcutt
Charles Geilfuss wrote:
> I've had the same experience with CF cards. As Chuck and others have
> pointed out, the CF cards seem pretty resistant to the type of use that
> would send an XD card into oblivion. I regularly delete photo files of any
> type (jpeg, RAW, TIFF) with the camera and my PC via a card reader with no
> thought of re-formatting and no problems. The only time I will format with
> the camera is if I have used a CF card to store any other type of data.
>
> Charlie
>
> On Wed, Jun 10, 2009 at 4:19 PM, Ken Norton <ken@xxxxxxxxxxx> wrote:
>
>> I erase, format, selective erase (oh no!) and just plain mutilate my poor
>> CF
>> cards in the E-1 and A1 cameras. I guess some makers got things right as I
>> don't run into problems except for this one odd thing that afflicts the
>> E-1.
>> I believe that erasing, instead of formating between dumps is ok if the
>> file-sizes are static. For example, my E-1 RAW files are all exactly the
>> same size. No fragmenting occurs. However, JPEG files are variable sized.
>> Whether this has anything to do with the price of tea in China, I have no
>> clue.
>>
>> AG
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