I agree about the SD controller being intelligent. But if the
controller is bad it is not going to diagnose it's own problems. Let
Windows (an external agent) do the checking.
I did not suggest two different runs of the Windows formatter (at least
on the same card). Just one run on each card to verify everything
works. I agree that the load leveler can place stuff wherever it wants
to but, when formatting, Windows (I believe) should immediately read
back the sector it just wrote. The leveler must return the same sector
wherever it located it physically or else it would be returning the
wrong data. Even if Windows waited to read back the entire disk in one
go it would still get the data from the same logical location it placed
it in even it the leveler chooses a different location on the next
write. But, in my test, there is no next write and the leveler causes
no confusion.
Note that I also suggested using a different card but only after testing
the first card.
I am unaware of SDFormatter and perhaps it has some magic of its own.
But I see nothing wrong with the simple test I described using what's on
the computer already.
I also disagree about what's the most important test. I think the most
important test was to see if the problem was (quickly) reproducible on
the same card. Brian's observation of the sequence he performed is
probably correct but memory is a fragile thing
Chuck Norcutt
On 6/18/2016 4:53 PM, Moose wrote:
On 6/18/2016 1:36 PM, Chuck Norcutt wrote:
See if you can reproduce the problem with a very deliberate test.
Regardless of the outcome, stick the card in your computer and format
it. Assuming Windows it will want to do a "quick format" and put a
check mark next to the "quick format" option. Uncheck the "quick
format" option. Tell it to go and be prepared to wait awhile. The
full format will write to every sector of the card and note any errors.
Yeah, well, if it were a HD, sure. But it's an SD card with load
leveling. The controller decides where to put stuff entirely aside from
what it tells the outside world. Two different runs of the Windoze
formatter the way you suggest may actually write to and read back
different physical memory for some the same reported locations. I
believe the SD controller is supposed to do its own evaluation(s) to
mark bad sectors as the card ages. Assuming the problem is the card, it
could be controller failure.
SDFormatter is a better bet. And using a different card altogether for
the test is a better test yet.
Relocable Moose
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