Verifying SD Cards

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I found an eBay vendor with a really *great* price on 64 GB microSDXC  
cards and ordered one ($11.50 shipped).  It was shipped from within the  
US so it came in a few days.  I've used H2testw to verify that it really  
is 64 GB and got this message... "Warning: Only 61052 of 61053 MByte  
tested."  A dialog pops up saying this is normal if you are using NTFS,  
but I formatted it in exFAT.  So is this a problem?

The intended use is in the rPi, so I will try firing that up later today  
and see if I can run a similar test there.  I'd like to verify the speed  
of the card.  What utility would be good for that?

If the card checks out I'm going to order several more.

--  

Rick C

Re: Verifying SD Cards
On 03/05/2016 15:54, rickman wrote:
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Not a problem.  I use h2testw for speed testing, but there are more  
comprehensive tests available too.

--  
Cheers,
David
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Re: Verifying SD Cards
Hi rickman,
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Really good price. I got some similar few month ago in Germany. 4 of 7  
where fake-SD with 8 to 16 GB but unuseable because the flashcontroller  
disturbes the card while repartitioning (with this trick I got some  
older fakes to work at least the available flash)

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No problem here. Do you really got SDXC speed? Mine are much slower.  
Don't matter for me, but it ist fake, too.

Marte

Re: Verifying SD Cards
On 5/3/2016 1:17 PM, Marte Schwarz wrote:
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I was reading something about being able to reprogram them back down to  
their "real" size, but it required a special manufacturer's burner  
thing, not sure if it was hardware or software.


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I just completed the H2testw pass and here are the results.

Warning: Only 61052 of 61053 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 20.8 MByte/s
Reading speed: 38.2 MByte/s
H2testw v1.4

I really don't get the price.  It is half the price of anyone else.  It  
does not come in a retail package.  Maybe they fell off a truck?  I'm  
ready to order five more, but the guy isn't responding.

--  

Rick C

Re: Verifying SD Cards
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Pretty good, but unless you need 100s of them  I'd stick with name
brand cards with known good performance for a few bucks more:

  http://www.adorama.com/ISGMBMC64DAA.html

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See here:
http://www.midwesternmac.com/blogs/jeff-geerling/raspberry-pi-microsd-card

Re: Verifying SD Cards
On 5/3/2016 4:42 PM, Paul Rubin wrote:
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So you think it is better to pay $18.99 for a Samsung EVO+ 64 GB rather  
than paying $11.50 for a Samsung EVO+ 64 GB?


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That was the article I read that shows the EVO+ to be near the top of  
the heap.

Funny though, he got 18.45 MB/s and 14.0 MB/s for read and write  
respectively on a 32 GB card while my 64 GB card shows 38.2 and 20.8 in  
comparison using a PC.  That's why I want to run tests on a Pi, so see  
if that is the difference or if the 64 GB card is faster than the 32  
which I doubt.  But who knows, maybe the 64 GB card has two chips that  
run in parallel.

I found a 128 GB card for just $8 with free shipping, but this one *has*  
to be fake.  I've got to buy it to see.  The really funny part is the  
guy is limiting you to just buying one every 10 days.  What's *that*  
about?  I'm thinking he doesn't want the nearly certain blowback from  
one guy buying a bunch of cards and them being crap.  He'd rather sell  
one each to a bunch of people most of who may not notice they were  
conned until after his check has cleared.  I won't be one of those, lol.

In researching how to test for fake cards, one page had a quote from a  
vendor that he had plenty of happy customers, regardless of the fact his  
cards were fake and ripping off so many including the brands he was  
copying.

--  

Rick C

Re: Verifying SD Cards
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The $11.50 card you got is an EVO+?  Hmm, you didn't mention that
earlier.  It's interesting and I wonder if it's real.  There could be
another level of fakery: you could conceivably have gotten an actual
64GB card that was not an EVO+.  I don't know what's happening with the
EVO+ cards though: prices are all over the place.

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Yep, or alternatively test a 32GB card on your PC.  Comparative tests
are way more believable if they're on the same hardware.

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I wouldn't.  I already know what to expect ;-)

Re: Verifying SD Cards
On 5/3/2016 11:43 PM, Paul Rubin wrote:
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Yes, I saw Best Buy have the best price of $9.99 or so on a 32 GB EVO+.  
  I figured rather than order it on Friday and get it later next week,  
I'd go to the store when it was convenient on Monday.  By Monday it was  
$14.99, the staff told me it had been on sale.  I found the web site  
prices (including Best Buy selling on eBay) to also be $14.99, lol.  But  
it was *still* on sale with a "regular" price of $25 or so.


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I don't care so much about the speed on the PC since it will be used on  
the Pi.  Many things affect the speeds, so testing on the PC is not  
really important to me.


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If it is fake, I'll just complain and they will refund my money or I'll  
refute the charge on the credit card.  Partly I want a chance to examine  
a fake card.  Maybe I shouldn't ask for my money back since I'll be  
getting what I expect, lol.

--  

Rick C

Re: Verifying SD Cards
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I think it was $11 at Adorama last time I looked.

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"If"?  ;-)

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Not a great idea to do a chargeback unless you really have to.  Like
landlord disputes, having a history of them tends to work against your
interests even if were are in the right about the underlying issues.

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Fair enough ;-)

Re: Verifying SD Cards
On 5/4/2016 12:40 AM, Paul Rubin wrote:
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Lol


My interests with *whom*?  But now you mention that, I'll use a  
different card than the one I usually use online.


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No, I may be expecting a fake card, but it is unlikely to be usable  
since on these fakes which are actually smaller than they report, writes  
to the memory that doesn't exist often craps on the lower memory that is  
actually there.  I don't feel at all guilty making the guy loose some  
money on the deal.  He's actually a criminal hurting both his buyers and  
the makers of genuine cards.

--  

Rick C

Re: Verifying SD Cards
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I'm told it's reported back to credit agencies so affects your general
credit score, though at a certain point you might not really care.

Re: Verifying SD Cards
On 5/4/2016 2:55 AM, Paul Rubin wrote:
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Told by whom?  In general, the credit score formula is not revealed and  
I've never seen anything to indicate this.  If this were true, it would  
have to *show* in your credit report.  I did a google search and found  
more than one page that says the opposite, disputing charges on your  
credit card will *not* damage your credit.

It's best not to spread rumors and other BS if you don't know it to be  
true.

--  

Rick C

Re: Verifying SD Cards
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On the Pi, have a look around /sys/class/mmc_host/ or
/sys/block/mmcblk or a similar location.  
This gives you parameters from the card itself - here's a list:
https://www.kernel.org/doc/Documentation/mmc/mmc-dev-attrs.txt

On a fake, these details are often bogus - for example a serial number of
'0' or '99' is suspect, while a serial of '24592839DFSDFJSD' is more
plausible (google it.  If someone else has the same serial number, something
is wrong)

This only works if you have a directly-connected MMC/SDHCI controller - not
if the card is attached by USB.

http://www.bunniestudios.com/blog/?page_id10%22
is the canonical reference for this kind of fishy-ness.

Theo

Re: Verifying SD Cards
On 5/4/2016 6:45 AM, Theo Markettos wrote:
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Thanks.  When I get my 64 GB card booted on the pi, I'll check the  
internal info.

--  

Rick C

Re: Verifying SD Cards
On 5/3/2016 2:33 PM, rickman wrote:
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I think it's better to pay $18.99 for a Samsung EVO+ 64GB rather
than paying $11.50 for one that may have a sticker that says
it's a Samsung EVO+ 64GB, but isn't.
Problem is that you have no way of telling which (if any) is the
real McCoy.

I wrote a little test program that tests for fakeness (less storage
than advertised) in a minute or so, but never had any SDXC cards
or reader to test it on.  Does work on 128GB USB3 sticks.

Back in the 16GB days, I used to take a laptop
to pickup Craigslist cards.  I disappointed more than a few sellers
when I verified that their cards were fake.  Don't think I ever found
a REAL 16GB flash card locally on Craigslist.

Speed has more than one dimension.  I only care about big file transfers
for backups and app-install files.  Can test that by copying a big
file with a program that shows the copy speed.  Gets a lot more complex
if you care about lotsa small files.
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Re: Verifying SD Cards

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  There are no McCoy brand memory sticks.

Re: Verifying SD Cards
On Wed, 04 May 2016 08:08:25 -0400

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    So if you see one you know it's been doctored.

    <sorry>

--  
Steve O'Hara-Smith                          |   Directable Mirror Arrays
C:>WIN                                      | A better way to focus the sun
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Re: Verifying SD Cards
On Wed, 04 May 2016 14:40:05 +0100, Ahem A Rivet's Shot  

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Could be it's dead, Jim.


--  
Bah, and indeed, Humbug

Re: Verifying SD Cards
Gave us:

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  I'm a doctor, Jim, not a memory card maker!

  "Brain, brain....  what is brain?"

Re: Verifying SD Cards
On Wed, 4 May 2016 14:40:05 +0100, Ahem A Rivet's Shot

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  Bob's yer uncle.

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