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Buying Bulk New/Used Micro SD Cards...

C

Computer Nerd Kev

Guest
Computer Nerd Kev <not@telling.you.invalid> wrote:
Clocky <nevergon@happen.com> wrote:
On 11/02/2020 4:00 am, Computer Nerd Kev wrote:

I\'d just rather not give the Chinese another chance to try and rip me off
again. Maybe as a last resort, but I can just see myself getting half of
the chips DOA and having to choose between buying from a good supplier
anyway, or waiting another month for SD cards from another cheap supplier
to come from China.

Sounds like you have been burnt a few times as I have.
I\'m a bit over getting fake, misrepresented and/or defective stuff from
China when it takes weeks to arrive.

Yeah, as much as possible I try to at least stick to things that are
fairly mechanical so that you can judge from the images and the look
of the items you get whether or not they\'ll do the job.

In this case there\'s also some risk that the cards might just be
unreliable (poor bond wire connection or something), or not work in
certain edge cases. So they might seem OK on first test but
everything starts going wrong later on.

Some years ago I read an article that I can\'t find now where someone
had decapped a variety of fake (but some very genuine looking)
micro SD cards and confirmed their origins by looking at the text
printed on the die and comparing to real cards from the manufacturer.
As I remember it, the author had been buying cards to go into
electronic devices that they were manufacturing there, and found a
batch where the fakes (which they\'d bought unknowingly) wouldn\'t work
in their devices like the real ones.
I finally found the article!

https://www.bunniestudios.com/blog/?page_id=1022

It seems that the controller chip and the programmed ID information
are more telling than the actual flash chip, which might be a
legitimate die that was originally rejected due to defects. Or the
card could be recycled, or programmed with a false capacity setting.

More SD card info here:
https://www.bunniestudios.com/blog/?p=3554

--
__ __
#_ < |\\| |< _#
 
M

~misfit~

Guest
On 3/11/2020 8:17 pm, Computer Nerd Kev wrote:
Computer Nerd Kev <not@telling.you.invalid> wrote:
Clocky <nevergon@happen.com> wrote:
On 11/02/2020 4:00 am, Computer Nerd Kev wrote:

I\'d just rather not give the Chinese another chance to try and rip me off
again. Maybe as a last resort, but I can just see myself getting half of
the chips DOA and having to choose between buying from a good supplier
anyway, or waiting another month for SD cards from another cheap supplier
to come from China.

Sounds like you have been burnt a few times as I have.
I\'m a bit over getting fake, misrepresented and/or defective stuff from
China when it takes weeks to arrive.

Yeah, as much as possible I try to at least stick to things that are
fairly mechanical so that you can judge from the images and the look
of the items you get whether or not they\'ll do the job.

In this case there\'s also some risk that the cards might just be
unreliable (poor bond wire connection or something), or not work in
certain edge cases. So they might seem OK on first test but
everything starts going wrong later on.

Some years ago I read an article that I can\'t find now where someone
had decapped a variety of fake (but some very genuine looking)
micro SD cards and confirmed their origins by looking at the text
printed on the die and comparing to real cards from the manufacturer.
As I remember it, the author had been buying cards to go into
electronic devices that they were manufacturing there, and found a
batch where the fakes (which they\'d bought unknowingly) wouldn\'t work
in their devices like the real ones.

I finally found the article!

https://www.bunniestudios.com/blog/?page_id=1022

It seems that the controller chip and the programmed ID information
are more telling than the actual flash chip, which might be a
legitimate die that was originally rejected due to defects. Or the
card could be recycled, or programmed with a false capacity setting.

More SD card info here:
https://www.bunniestudios.com/blog/?p=3554
Interesting reading but very dated now.

I have a Samsung 128 GB SD card in my Nokia 4.2 Android phone and the phone thinks it\'s a 256 GB
card that\'s half full already (but can\'t show the contents of that half).

When I used this card previously in a Windows 10 computer it read it correctly as a 128 GB card.
Without further info I\'m assuming that Samsung use the same controller chip / NAND in their 128 and
256 cards (they\'re rated for the same speeds).

I wonder if the controller chip, being the same as for a 256 is read by the phone initially as a
256 then gives the phone a signal that only half is available. Or if there actually IS 256 GB but
with faults in half of the NAND so half is marked as \'full\' on the card and that\'s why the phone
reports it as it does?
--
Shaun.

\"Humans will have advanced a long, long way when religious belief has a cozy little classification
in the DSM\"
David Melville

This is not an email and hasn\'t been checked for viruses by any half-arsed self-promoting software.
 
C

Computer Nerd Kev

Guest
~misfit~ <shaun.at.pukekohe@gmail.com> wrote:
On 3/11/2020 8:17 pm, Computer Nerd Kev wrote:

Some years ago I read an article that I can\'t find now where someone
had decapped a variety of fake (but some very genuine looking)
micro SD cards and confirmed their origins by looking at the text
printed on the die and comparing to real cards from the manufacturer.
As I remember it, the author had been buying cards to go into
electronic devices that they were manufacturing there, and found a
batch where the fakes (which they\'d bought unknowingly) wouldn\'t work
in their devices like the real ones.

I finally found the article!

https://www.bunniestudios.com/blog/?page_id=1022

It seems that the controller chip and the programmed ID information
are more telling than the actual flash chip, which might be a
legitimate die that was originally rejected due to defects. Or the
card could be recycled, or programmed with a false capacity setting.

More SD card info here:
https://www.bunniestudios.com/blog/?p=3554

Interesting reading but very dated now.
Current until SD cards (and their underlying communication standards)
are replaced by something newer that implements a reliable
authentication system, in my opinion.

I have a Samsung 128 GB SD card in my Nokia 4.2 Android phone and the phone thinks it\'s a 256 GB
card that\'s half full already (but can\'t show the contents of that half).

When I used this card previously in a Windows 10 computer it read it correctly as a 128 GB card.
Without further info I\'m assuming that Samsung use the same controller chip / NAND in their 128 and
256 cards (they\'re rated for the same speeds).

I wonder if the controller chip, being the same as for a 256 is read by the phone initially as a
256 then gives the phone a signal that only half is available. Or if there actually IS 256 GB but
with faults in half of the NAND so half is marked as \'full\' on the card and that\'s why the phone
reports it as it does?
I\'d guess that it\'s probably just a bug in the firmware, akin to how
the same thing used to happen with HDDs in PCs if the BIOS\'s
automatic CHS value detection got the wrong values and set up the HDD
as if it were larger than it actually was.

SD cards are more complicated, but I\'ve forgotten too much of how
they work now to remember whether there are multiple ways of
determining the total storage space. At a minimum I guess there\'s
partition size Vs device storage size - maybe you\'ve somehow got
a partition that\'s twice as large as the total storage space?

--
__ __
#_ < |\\| |< _#
 
M

~misfit~

Guest
On 6/11/2020 10:38 am, Computer Nerd Kev wrote:
~misfit~ <shaun.at.pukekohe@gmail.com> wrote:
On 3/11/2020 8:17 pm, Computer Nerd Kev wrote:

Some years ago I read an article that I can\'t find now where someone
had decapped a variety of fake (but some very genuine looking)
micro SD cards and confirmed their origins by looking at the text
printed on the die and comparing to real cards from the manufacturer.
As I remember it, the author had been buying cards to go into
electronic devices that they were manufacturing there, and found a
batch where the fakes (which they\'d bought unknowingly) wouldn\'t work
in their devices like the real ones.

I finally found the article!

https://www.bunniestudios.com/blog/?page_id=1022

It seems that the controller chip and the programmed ID information
are more telling than the actual flash chip, which might be a
legitimate die that was originally rejected due to defects. Or the
card could be recycled, or programmed with a false capacity setting.

More SD card info here:
https://www.bunniestudios.com/blog/?p=3554

Interesting reading but very dated now.

Current until SD cards (and their underlying communication standards)
are replaced by something newer that implements a reliable
authentication system, in my opinion.

I have a Samsung 128 GB SD card in my Nokia 4.2 Android phone and the phone thinks it\'s a 256 GB
card that\'s half full already (but can\'t show the contents of that half).

When I used this card previously in a Windows 10 computer it read it correctly as a 128 GB card.
Without further info I\'m assuming that Samsung use the same controller chip / NAND in their 128 and
256 cards (they\'re rated for the same speeds).

I wonder if the controller chip, being the same as for a 256 is read by the phone initially as a
256 then gives the phone a signal that only half is available. Or if there actually IS 256 GB but
with faults in half of the NAND so half is marked as \'full\' on the card and that\'s why the phone
reports it as it does?

I\'d guess that it\'s probably just a bug in the firmware, akin to how
the same thing used to happen with HDDs in PCs if the BIOS\'s
automatic CHS value detection got the wrong values and set up the HDD
as if it were larger than it actually was.

SD cards are more complicated, but I\'ve forgotten too much of how
they work now to remember whether there are multiple ways of
determining the total storage space. At a minimum I guess there\'s
partition size Vs device storage size - maybe you\'ve somehow got
a partition that\'s twice as large as the total storage space?
Perhaps. I let the phone format the card as I\'d been using it formatted NTFS (128 GB, as recognised
by the computer) in an SD Card - USB3 adapter for a few months with Windows 10.

I forgot that when I put it in the phone and it said \'unrecognised file system\' and asked to format it.
--
Shaun.

\"Humans will have advanced a long, long way when religious belief has a cozy little classification
in the DSM\"
David Melville

This is not an email and hasn\'t been checked for viruses by any half-arsed self-promoting software.
 
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