A friend called me saying his 1TB SD Card he was using for backup stopped working on Windows & MacOS

A friend called me saying his 1TB Lexar SD Card he was using for backup
suddenly stopped working on Windows & MacOS.

Is there a tool to check a card that won't even show itself to the desktop?

It doesn't show up in the Windows Device Manager.

He tried a bunch of physical tricks (e.g., clean contacts, tape over notch,
write tab flipping back & forth, etc.) where this question is about
troubleshooting the card itself.

Other cards work fine so it's the card - not the desktop.

Any suggestions to figure out what's wrong with the SD card?

On 05/08/2019 05.14, Arlen G. Holder wrote:
A friend called me saying his 1TB Lexar SD Card he was using for backup
suddenly stopped working on Windows & MacOS.

Bad idea.

Don't use something that is prone to fail, so big and expensive. Use a
real hard disk or an SSD.

Yes, there is specific software for testing cards. I do not remember the
name.

--
Cheers, Carlos.

Arlen G. Holder wrote:
A friend called me saying his 1TB Lexar SD Card he was using for backup
suddenly stopped working on Windows & MacOS.

Is there a tool to check a card that won't even show itself to the desktop?

It doesn't show up in the Windows Device Manager.

He tried a bunch of physical tricks (e.g., clean contacts, tape over notch,
write tab flipping back & forth, etc.) where this question is about
troubleshooting the card itself.

Other cards work fine so it's the card - not the desktop.

Any suggestions to figure out what's wrong with the SD card?

Since counterfeits are a common occurrence with flash
devices, you quick-format the device (NTFS or ExFAT)
and write a file which is very close to the full storage
capacity of the device.

Then, you read back the file (the checksum function
on 7ZIP works nicely for this).

If the ingoing checksum and the returning checksum
are the same, the device passes.

In the case of the Lexar 1TB SDXC, it would take
3 hours to write, and 3 hours to read back. So in
six hours, you know whether it is counterfeit or not.

The devices had an MSRP of $500. If you buy one for
$10 (2% of the MSRP), then it should take relatively little time to
discover it's a counterfeit. (The rollover on the
address will happen quickly.)

Paul

"Arlen G. Holder"
Mon, 05 Aug 2019 03:14:56 GMT in
alt.comp.freeware, wrote:

A friend called me saying his 1TB Lexar SD Card he was using for
backup suddenly stopped working on Windows & MacOS.

Is there a tool to check a card that won't even show itself to the
desktop?

Yes, but, with limitations...IE: a drive letter isn't mandatory but
device manager has to see the hardware.

It doesn't show up in the Windows Device Manager.
He tried a bunch of physical tricks (e.g., clean contacts, tape
over notch, write tab flipping back & forth, etc.) where this
question is about troubleshooting the card itself.

Other cards work fine so it's the card - not the desktop.

Any suggestions to figure out what's wrong with the SD card?

If you know for sure it's not a driver issue, then I have several
suggestions which may infact, fix the issue and regain you access to
the drive contents. None of them are free though.

Due to your past history with me, I need to know if your friends data
is worth paying for before I provide options. If it's not, then he
might as well purchase another drive and be done with it at this
point. You aren't going to find a simple freeware solution to this
problem - You have a hardware problem. A specific type of hardware
problem...The data itself is probably very much intact, but, there's
more to those drives than just memory chips. [g]


--
Does killing time damage eternity?

On Mon, 5 Aug 2019 06:43:32 -0000 (UTC), Diesel wrote:

Due to your past history with me, I need to know if your friends data
is worth paying for before I provide options.

Same old routine. So looking forward to watching this go nowhere.

Sent from my iFurryUnderbelly.

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On 05/08/2019 07.00, Paul wrote:

....

The devices had an MSRP of $500.

I can not understand expending that on a flash stick when SSD is cheaper
and better :-(

As a method to transport movies, perhaps... if it is fast write. As a
backup device? Never.

--
Cheers, Carlos.

Carlos E.R. wrote:
On 05/08/2019 07.00, Paul wrote:

...

The devices had an MSRP of $500.

I can not understand expending that on a flash stick when SSD is cheaper
and better :-(

As a method to transport movies, perhaps... if it is fast write. As a
backup device? Never.


It's intended for DSLR video recordings.

I have a 32GB SD in my little point and shoot,
and I've never filled it up. The price was reasonable.
Ten minutes of video doesn't even make a dent.

The $500 one might be sufficient for 4K video recording work.

It really shouldn't be used for other purposes, because
as you point out, there are so many superior storage
solutions you could buy with $500.

The attraction of the SD or microSD, is it
"fits in your camera". The internal flash storage
on my camera would not last very long, without the
adjunct storage added. And my SD chip is only Class 10,
just good enough for HD video.

Paul

On Mon, 05 Aug 2019 11:28:45 -0400, Paul wrote:

It's intended for DSLR video recordings.

The friend told me he used it because he bought a few for his drone.
It turned out to be convenient in that it was always in the laptop.

On the topic of choice, is an SD card really less reliable?
How would he have known that?

For example, it's just flash memory, right? If it's just flash memory, why
would flash memory in an SD card be any more or less reliable than flash
memory in a memory stick or in an external SSD drive?

I am not saying it's more or less reliable as I don't know - but do we have
any evidence that SSD bits are less reliable than any other similar bits?

Anyway, the main question is whether there is a 'trick' to get Windows to
recognize it, which doesn't seem to exist, to date?

Arlen G. Holder wrote:
On Mon, 05 Aug 2019 11:28:45 -0400, Paul wrote:

It's intended for DSLR video recordings.

The friend told me he used it because he bought a few for his drone.
It turned out to be convenient in that it was always in the laptop.

On the topic of choice, is an SD card really less reliable?
How would he have known that?

For example, it's just flash memory, right? If it's just flash memory, why
would flash memory in an SD card be any more or less reliable than flash
memory in a memory stick or in an external SSD drive?

I am not saying it's more or less reliable as I don't know - but do we have
any evidence that SSD bits are less reliable than any other similar bits?

Anyway, the main question is whether there is a 'trick' to get Windows to
recognize it, which doesn't seem to exist, to date?

At some level, all storage is the same.

Storage devices are black boxes.

They can fail at any time.

How can we protect ourselves ?

Own two of them. Put copies of the same materials on both.

*******

The rest of the thoughts on the subject are just noise.

*******

If you keep the concept simple for people,

"keep two copies of materials on physically separate devices"

then we might arrange to reduce the amount of lost data.

Then, *test* the people, by asking them to show you
the two copies of data. For example, if your friend
shows you the $500 SD card, ask to see a copy of
*each and every file on there*, being stored on
a second device. My guess is, the materials on the
SD are all unique, and *only-copies*. No redundancy
to be found in the computer room.

Just because there happens to be "a little bit of data
recovery capability" with hard drives, does not mean
we go around with only the one hard drive, containing
only the one copy of important files. Because of intangibles
like Ransomware, there are still good reasons for additional
copies "protecting against the unthinkable".

When the head lock jammed on my Barracuda 32550N, leaving
a *gouge* in the platter, was I thinking a data recovery
company was going to save my ass ? No, because just the
noise that came out of the drive that day, told me everything
I needed to know. I didn't even need to power up the
device a second time - that's how awful the noise was.

This might be the reason today, the same head lock
mechanism does not exist.

*******

Characteristics:

Hard drive - has SMART
- degradation tends to be gradual on modern devices,
unless there is a firmware bug. (The "dead after
thirty days" bug being an example.)
- some simple data recovery procedures help
with a percentage of the failures. This cannot
be considered good enough for disaster recovery.

SSD drive - has SMART
- degradation can be faster. Early generations bricked.
- no particularly noteworthy test tools.

SD - no SMART
- no tools

Take your pick. SD is fine, if you have two identical ones.
And you don't hold both of them up to the same ionizing
radiation source at the same time.

HTH,
Paul

On Mon, 05 Aug 2019 12:56:18 -0400, Paul wrote:

At some level, all storage is the same.

Hi Paul,
Thank you for understanding the question, since some people said that "sd"
bits are somehow (magically?) less reliable than "ssd" bits.

I'm not saying they're more or less reliable (as I have no clue) - I'm just
asking what facts they used to come to those assessments.

Storage devices are black boxes.
They can fail at any time.

They can, and do.

How can we protect ourselves ?
Own two of them. Put copies of the same materials on both.

Understood that redundancy is a good thing.

My main sub-topic question is what facts do people use to assess that sd
bits are less reliable than, oh, say, ssd bits?

Hard drive - has SMART
SSD drive - has SMART
SD - no SMART

OK. This is the first fact I've seen, and I don't disagree with it.
It's a good fact, in fact.

Take your pick. SD is fine, if you have two identical ones.
And you don't hold both of them up to the same ionizing
radiation source at the same time.

The fact the data on the SD card is a backup is already a "redundancy" of
sorts, although, as you noted, it's not precisely exact except at just the
one point in time of the backup.

In this case, the owner has ditched the expensive SD card - but the
question remains if there is any way to resurrect it - not for the data -
since it was, after all, only a backup, but for the technical ability to
resurrect an sd card that Windows won't see.

Arlen G. Holder wrote:

In this case, the owner has ditched the expensive SD card - but the
question remains if there is any way to resurrect it - not for the data -
since it was, after all, only a backup, but for the technical ability to
resurrect an sd card that Windows won't see.

If we're at the factory, standing in front of the machine
that programs them, the answer is probably "Yes".

Standing at any other point on the Earths surface,
the answer is more likely to be "No".

Now, we did say "resurrect".

That's different than "data recovery".

*******

This sample pretends to show what is inside.

https://en.wikipedia.org/wiki/File:P...r_20090420.jpg

Notice in that one, they went from a discrete controller
chip, to a silicon die with a glob-top.

Probing the Flash chips where the leads solder to
the PCB should be possible. You would need to access
a land on the controller chip (TRST) to cause the
controller to tristate and not drive the flash bus.

Then, you could scan out the flash chip.

The flash chip may or may not be alive.

Ultimately, if the device has a high enough
capacity, the controller might be right on the
Flash chip itself, which would make probing
more difficult. The chip may not have sufficient
pinout for scanning purposes. If it had JTAG, you
could bit-scan the chip (which would take weeks to do).

Devices evolve faster than pictures can be
added to Wikipedia. To place 1TB on an SD,
would not exactly be easy. The chip to do that
isn't likely to be that tiny.

You can only "layer" so many chips, before
the sandwich becomes too thick. Or the bus
capacitance is too high to drive the sandwich.
For devices of this sort, they don't normally
dwell on how they are constructed.

Paul

On Mon, 05 Aug 2019 13:58:34 -0400, Paul wrote:

Now, we did say "resurrect".
That's different than "data recovery".

Hi Paul,
Mea culpa on the terminology.

I should be very clear that the goal is not the data itself since it's just
a backup after all, where we're mostly asking for your experienced judgment
and assessment of the facts as you know them.

The problem for the friend is that the card was expensive, and maybe, just
maybe, there's a "minor thing" that needs to be fixed (sort of like the
kind of stuff that a format fixes, for example).

If the card hardware is dead - the card hardware is dead.

What's interesting is that nobody here seems surprised that card hardware
would just die like that - so maybe it's really common (dunno).

Mostly we just want to learn what went wrong and what can be done, if
anything, to get Windows to recognize the card again, although who would
trust a card for backup that pulls this kind of trick on us.

From a standpoint of statistics, does it surprise you or not that a "card
just died" like that? Are they normally not recoverable? Or would a format
of some sort work (if Windows would just recognize the card that is)?

Arlen G. Holder wrote:
On Mon, 05 Aug 2019 13:58:34 -0400, Paul wrote:

Now, we did say "resurrect".
That's different than "data recovery".

Hi Paul,
Mea culpa on the terminology.

I should be very clear that the goal is not the data itself since it's just
a backup after all, where we're mostly asking for your experienced judgment
and assessment of the facts as you know them.

The problem for the friend is that the card was expensive, and maybe, just
maybe, there's a "minor thing" that needs to be fixed (sort of like the
kind of stuff that a format fixes, for example).

If the card hardware is dead - the card hardware is dead.

What's interesting is that nobody here seems surprised that card hardware
would just die like that - so maybe it's really common (dunno).

Mostly we just want to learn what went wrong and what can be done, if
anything, to get Windows to recognize the card again, although who would
trust a card for backup that pulls this kind of trick on us.

From a standpoint of statistics, does it surprise you or not that a "card
just died" like that? Are they normally not recoverable? Or would a format
of some sort work (if Windows would just recognize the card that is)?

It's pretty easy to understand.

A Critical Data section got erased... somehow.

Critical Data is anything the controller needs, to maintain
error-free data.

If the integrity of the error-free data can no longer be
guaranteed, the controller "closes up shop".

Critical Data storage is on a section of Flash which
is SLC-like (10K to 100K writes), or NOR flash (1 million
writes). Maybe when a bad block is spared out, an indirection
table needs to be updated. Maybe the flash device has
real honest-to-goodness wear leveling, in which case
a rather large table needs to be maintained.

The device has to write and maintain things like this,
without benefit of a Supercap or Advanced-Power-Fail
notification. Perhaps each time the power comes on,
it "scans" the existing record and condenses it
so the state is current.

In any case, after an interval of "trouble" (the user
sees a pronounced performance drop), during that interval
the Critical Data storage could be taking a pounding
as "bad" events are recorded one way or another.
Either the Critical Data storage fails (no longer
write-able), or the firmware in the controller
"pulls the plug" and stops responding.

This is a way of saying to the user, "you should be
using your other $500 SD card right now, because this
one is toast".

Storage devices never seem to be "defensively designed".
There's no such notion of "always responding", "log is
available with fatal error as the last entry". No root
cause easily accessible. Just *bam*, dead.

A good business to be in, don't you think ?

Now, at least on hard drives, there is a TX,RX,GND
header or interface, for "talking" to the drive.
But the language of the drive is cryptic, so you
cannot hope to query the thing while holding
a copy of "Disk Drives for Dummies" in your hand.
It's always possible an interface like that, or
a serial JTAG interface is available. For the SD,
I'm sure their "secrets" are well-hidden.

A processor and firmware are involved. The processor
buses are not pinned out. You can't "trace execution".
That's an example of what kind of barrier you might
face working with it.

Paul

On Tue, 06 Aug 2019 14:21:58 -0400, Paul wrote:

A processor and firmware are involved. The processor
buses are not pinned out. You can't "trace execution".
That's an example of what kind of barrier you might
face working with it.

Thanks Paul for that realistic assessment of what can be done to notice
when an SD card is going bad, before it fails, and what's the less than
optimistic chances of recovery.

I guess I'll have to take Diesel up on his always make-believe offers of
his sheer genius, where he and nospam should go into business together what
with all their claims of imaginary functionality overall.

The suggestion to be wary of a card 'acting up' is useful - as is the fact
there is no SMART for it. Seems to me expensive SD cards aren't worth the
trouble, but these aren't mine so I can't say what others do.

Thanks for always being purposefully helpful, where your pessimistic
response tells me what I need to know - as I trust you as you've always
been both purposefully helpful and credible (as am I, because I care).

Thanks.

On 05/08/2019 19.29, Arlen G. Holder wrote:
On Mon, 05 Aug 2019 12:56:18 -0400, Paul wrote:

At some level, all storage is the same.

Hi Paul,
Thank you for understanding the question, since some people said that "sd"
bits are somehow (magically?) less reliable than "ssd" bits.

I'm not saying they're more or less reliable (as I have no clue) - I'm just
asking what facts they used to come to those assessments.

Just that we have read from magazines and people that know, that they
are in fact less reliable. That doesn't mean we store in biological
memory the reports or explanations why this is so: we only store the
fact "don't rely too much on flash cards or sticks".


Just google "are memory cards less reliable than ssd disks?"

First hit says:

They have fewer components and are far more robust, but are restricted
to a finite number of write cycles usually in the range of 3,000 to
5,000. And since they tend to use cheaper memory modules, they can be
less reliable than SSDs. ... As with SSDs, data retention is affected by
the health of the memory blocks.11 mar. 2015

Or this one:

https://www.maketecheasier.com/sd-card-vs-ssd/
SD Card vs. SSD: What Is Really the Difference?
By Miguel Leiva-Gomez – Posted on Sep 15, 2017 in How Things Work

It is a long article, I will not excerpt it. Google does:

15 sept. 2017 - Both SD card and SSD use solid-state storage and have no
moving ... The solid state drive has given us a leap forward in the
ability to ... This is not to say that there aren't different types of
NAND flash memory, ... The entire infrastructure of the SSD is built to
ensure that no single cell is used more than the ...


The last sentence is a hint of what you should look at.


--
Cheers, Carlos.