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Old May 23rd 18, 01:55 PM posted to alt.comp.os.windows-10
Lucifer Morningstar[_3_]
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Posts: 33
Default USB thumb drives.

On Wed, 23 May 2018 06:24:51 -0400, Paul
wrote:

wasbit wrote:
"Paul" wrote in message
news
wasbit wrote:
"Paul" wrote in message
news
Time for the testing tools.

https://www.raymond.cc/blog/test-and...-with-h2testw/



######################
Chip Genius

Controller Vendor: Alcor Micro
Controller Part-Number: AU6989SN-GTB/AU6998SN [F206] - F/W FA02
Flash ID code: ADDE14AB - Hynix H27QCG8D2F5R - 1CE/Single
Channel [MLC-16K] - Total Capacity = 8GB

Proving once again, that you really can get $13 worth
of storage, by paying $13 :-)

I take it, when they modified the declaration on the
drive, the controller was limited to declaring 2TB
and could not declare a larger number. Or they would
have set it to an even higher number.


So how does this magic trick work?
The drive has been formatted, rewritten with 1242 (242 GB) videos &
several instances of your big.bin files. Windows shows 411 GB used & 505
GB free space.
Having transferred the drive from my desktop to a laptop running Linux
Mint, (I'm a novice), so as to isolate it from the original file source,
a notification pops up saying all the contents could not be displayed.
Free space is 543 GB because several of the bin files aren't showing.
All the video files played from a random selection.
To my mind, it would seem there is much more than 8 GB available
although I wouldn't trust the drive for anything important.


You can disassemble the Flash stick and verify the chip
part number, if you don't believe the output of the
Chip Genius. That's one way to resolve any uncertainty.

*******

The controller can have a couple of behaviors.

1) Chip designers never intended to support fraud.
2) Chip designers actively supported the sale of fraudulent sticks.

In the first one, there is a single register, and by
inflating the capacity to 2TB, the address "rolls over"
when writes pass the 8GB point. Say, for example, you
wrote 242GB of material to the stick. The address
used at that point would be (242GB mod 8GB) and the
stick would actually be writing blocks at the 2GB point.
242 divided by 8 goes 30 times, with 2 left over as
a remainder. And that's what the "mod" tells you.

If the design worked that way, then Windows should be
quite upset, right after you write slightly more than
8GB of materials. If you wrote to 8GB+one_sector,
then the NTFS file header would get overwritten
by the file you were trying to transfer. Windows
should be ****ed.

The other behavior they could put in the design, is two
registers. One register contains the "real" chip capacity
of 8GB, while a second register is used as a value returned
when Windows queries the available device size. By doing
it this way, instead of implementing address rollover with
the mod() function, they can instead "clip" the address.
Then, any address greater than 8GB, simply results in the
write operation being blocked. This ensures integrity for
anything written below 8GB, but nothing written above 8GB
comes back with anything other than zeros. This behavior
requires the designers to be "in on the fraud concept"
and using two registers for the express purpose of allowing
"inflated" sticks to be sold.

But no matter how you slice it, if the chip really is 8GB,
it cannot hold more than 8GB of data. All it takes is
someone making a test file from /dev/random, a file with
high entropy, that will defeat any compression mechanisms
and ensure an honest test result. And they'll immediately
be able to tell it isn't a 2TB drive.


I got caught in a scam where I bought what I thought was
a 4 gig mp3 player. Turned out to be a 1 gig player that
had been hacked to show 4 gig to windows.
Once I tried to put more than 1 gig on it windows complained
of write errors.

Paul

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