On Dec 4, 2006, at 10:23 AM, Godfrey DiGiorgi wrote:

> another reason why you want to do formats with the camera is that
> with flash media you want to avoid writing to media needlessly ... it
> has a finite lifespan. This is why formatters for flash media
> typically do not zero the files, just replace the directory tables.
> they also reposition the directory tables as time goes on if the
> media is used a lot, again to preserve and extend the media's  
> lifespan.

The number of times you can flip a bit on a modern NAND cell is  
supposed to be somewhere around 1,000,000 times.  My understanding is  
that the wear-level functionality of a flash device is internal to  
the flash device itself; when the flash device tries to write to a  
bad block and fails, it automatically allocates a different block and  
marks the bad block as unavailable.  The electronic device accessing  
the flash chip is unaware that this happens.  According to the  
device, whether it be a camera or otherwise, it appears to be a FAT  
disk, when actually there is a translation layer in the flash device  
that handles the lifting behind the scenes.

Michael

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