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Surface Test for Flash Drive

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ziloo

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Feb 7, 2006
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Hello Folks,

My USB Flash drive was acting up on me; whenever I deleted a file, the name
would still be on the directory list showing 0 kb size! Using a partition manager
software, I tried a "surface test??????" just for the heck of it......not knowing
whether it is possible for flash hardware! The result was a "OK" for the test;
however when I tried to format the drive (FAT32), the process failed.

Any educational/advisory comment is much appreciated!


ziloo :mrgreen:
 
Flash media has a finite number of writes.

It is also possible if the thumb drive was a counterfeit that it lied about how big
it actually was.
 
I have been using that flash for a few years, and originally it came with
a three year warranty. I am more curious about "surface test" procedure and
not being able to format the media?

ziloo :mrgreen:
 
Not knowing which surface test is being used, I can only speculate. Most of the surface test programs write a sector and then immediately read it back. Flash drives tend to cache writes in memory until a block is ready to be written. Therefore, the immediate read may happen before anything was written to flash chips and the test will succeed even though the write will eventually fail.

https://goughlui.com/2017/05/30/experiment-8gb-usb-flash-drive-endurance-test/ is one of the better explanations of how flash drives fail over time.
 
A surface test is quite pointless for a flash drive (due to wear-leveling, transparent error-correction, and general abstraction by the flash controller) and also a good way to kill a flash drive fast...

The issue you have is not related to the flash drive but to Windows. I had this bug too for quite a while on my hard disk until I found it was because of some fundamental Windows service not running. Can't remember what service it was exactly, however.
 
Just read testing probably won't do much, chances are something got corrupted and the corrupted data will read back "fine".

What I would to is attach it to a Linux system and "dd" the entire drive device with zeros. Then create a new partition and reformat. (Windows tries to hide partition info from you, but there is probably some tool for this)

If you want to be sure the drive is retaining data, fill the drive up with some large ZIP file and read it back or test the zip integrity.
 
Some flash drives have an "secure erase" function that essentially sets the drive back to zero. There are various utilities floating around for this--even in Linux.

I've had to do this when an SSD essentially ground to something approaching molasses in January. Secure erase, reload and everything's fine.
 
The interesting part is that formatting the flash drive has failed on Windows as
well as other professional partitioning software. After I finally "erased" the
FD, Windows Explorer shows that the used part of the drive is 0 and
the free part of the drive is also 0! Then....the formatting fails...
In the words of McCoy (the Star Trek universe)........Jim........he is dead!

ziloo :mrgreen:
 
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