On 11-03-14 9:07 PM, steve harley wrote:
On 2011-03-14 18:37 , Bruce Walker wrote:
On 11-03-14 5:21 PM, steve harley wrote:
On 2011-03-14 14:54 , Bruce Walker wrote:
Now if a bad block is discovered on your Flash device while trying to
read the directory structure, I assume that the bad block will
immediately be remapped, but the damage is already done. Not
physically
damaged of course, but files could appear to be unreadable, contain
holes, etc. The fix is to format the card and that will replace the
directory structure. Life goes on.
formatting won't fix a bad block, the image file that is thus
"damaged" should just be deleted
Steve, I didn't say that. I said that formatting would fix a screwed-up
directory structure (and/or files) caused by their having been a bad
block in the directory structure itself. The odds of that happening are
relatively high because the directory structure is updated for very many
file operations, like opening and closing them.
makes more sense when you say it that way -- it sounded like a
different claim when i read "contain holes" (i.e. the remapped block
is in a file) followed by "the fix is to format" -- yes, some blocks
used for the directory are written fairly often (though not
necessarily when opening a file)
of course reformatting frequently will increase the number of writes
of those directory blocks, and thus wear those blocks out even faster
Yeah, exactly, which is one reason why I don't habitually format; I just
erase the images.
But these cards are quite smart and vastly improved over earlier Flash
tech. As blocks wear out they are remapped to other unused blocks. Over
time the card just appears to have reduced capacity. So overall you'll
get much better lifetime out of them than earlier generations would have
provided. I don't think the "10K write cycles" thing is much of a real
issue for average users anymore.
-bmw
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