On 6/18/2016 2:37 PM, Chuck Norcutt wrote:
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.
Nor was I suggesting doing that. I was using it as an example, to point out that it does not test the entire memory in
any one application.
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.
Still not a test of all the memory. Actual memory is larger than available memory, and which subset is used/available
changes. If there's bad memory that caused Brian's problems, there is no guarantee that a complete format will access it.
This is also the problem with the 'intentional test'. Even if one deletes exactly the images where the problem lies,
then shoots new ones through and past it, there's no guarantee the new files will be stored in the same physical memory
locations as the ones before.
Note that I also suggested using a different card but only after testing the
first card.
And I think that's not the best procedure. We don't know if the card is the problem, internally, if there is an iffy
electrical connection to the camera or if the camera is at fault. First priority is to establish where the problem lies.
Substitution of components is the most direct way to find the location of a fault.
Absent a second camera and without a way to access and test/clean the internal connections down that thin, deep little
hole, the logical first step is to use another card or cards, cleaning the contacts before use.
Knowing nothing about the card in question, I also can't rule out the possibility that it is a fake. There have
apparently been a lot of those running around, at least sometimes. One of their characteristics, I gather, is missing or
unreliable memory above a certain level.
'Twere me, I'd use one of my newest cards, a name brand, purchased from a major dealer in a tamper resistant package.
Then, for the reason above, I think the only course is to pay close attention as I go about my usual use. And the card
that was there when the fault happened would go into quarantine.
If the problem fails to resurface, time to throw away the bad card. A bunch of reformatting and so on is just a waste of
time and effort; cards are so cheap. I just ordered a spare 64 GB, Sony UHS3, for $24. If the failure remains, time to
hope the camera is in warranty.
I am unaware of SDFormatter and perhaps it has some magic of its own.
I don't know much about it either, except is seemed sensible to use the tool provided by the makers' association.
<https://www.sdcard.org/downloads/formatter_4/>
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
You've jumped to the assumption/preliminary conclusion that the card is at fault. Had you any basis for that other than
a guess, I'd agree. Given the extremely limited information provided, I think a more generalized troubleshooting
approach is appropriate. The camera is, for example, a far more complex device than the card, so one might conclude
logically that it has a higher likelihood of failure.
Isn't there a whole field/discipline around failure analysis and troubleshooting? I think with your background, you
should know it better than I.
I've never had a flash card fail, from those flat, small credit card shaped things for early Oly digicams to the latest
SD types. I have had a couple of digital cameras fail, not in image writes, but still, more failures than of cards.
It's so easy to go down a rabbit hole and waste a lot of time based on unsupported assumptions. I'll bet you don't need
to ask how I know. :-)
Logical Order Moose
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What if the Hokey Pokey *IS* what it's all about?
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