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Advice for Testing USB Sticks and Data Recovery Tools

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brahman:
Hello,

in my experience with USB sticks a brand new purchase may have a problem right away. If so immediately return it and do not use it. There were also a lot of fakes on the markets, which had a real size  of only 512MB, but made Windows think successfully that the size was several GB. It also allowed Windows to copy data in that amount (built the Fat with the filenames so that the files appeared to bo on the stick even when searchng for them later, but all the data went into the toilet WITHOUT ANY ERROR MESSAGE WHILE COPYING). These fakes can only be detected with special tools, since the controller is adjusted to show let's say 8GB, but there is only 512MB memory in it. Worse, problems will only show up, if you try to put more than 512MB of data on this stick and afterwards check all the data with a compare utility, since the file is registered in the file system and any file commander shows it to be on the disk, though it is not.

Because of wear leveling (the controller switches data to different sectors to increase life expectancy of the memory chips on write operations) USB sticks cannot be easily handled by standard hard drive diagnostic utilities. One give away for a fake stick though is a GRAPHED speed bench mark test: The REAL chip will be slow, and then the rest of the test will show unrealistically FAST results.

Like this fake 1 GB USB drive with only 256MB on board where the real chip is about 12,5MB/sec but the stick controller lets the data pass for the non-existent chips at 25MB/sec.:

Advice for Testing USB Sticks and Data Recovery Tools

There is one free utility specially for USB sticks which a big German software magazine developed after they sent out a few hundred (at least) of those fake sticks to their users as gifts for subscribing to their magazine (and subsequently had to replace them all!).

I run this tool on all my USB sticks when first purchasing them.

It works best when the stick is formatted but completely empty, since it fills the stick up to capacity with its own data and then makes a byte by byte comparison. This way it bypasses the wear leveling and caching of the USB stick and can test every single sector. I would recommend to format the stick as Fat/Fat32 for testing, and only after first testing format to NTFS if so desired.

The program itself can be switched from German to English when started, but the web site is German only.

Here is the link to the website translated by google:

http://translate.google.com/translate?prev=hp&hl=de&js=n&u=http%3A%2F%2Fwww.heise.de%2Fsoftware%2Fdownload%2Fh2testw%2F50539&sl=de&tl=en&history_state0=&swap=1

Here is the original German link:

http://www.heise.de/software/download/h2testw/50539

Here is the link for directly  downloading the utility (which is a bit difficult to find):

http://www.heise.de/ct/Redaktion/bo/downloads/h2testw_1.4.zip

If you do have data problems on a stick already in use, I would recommend the excellent free Testdisk and Photorec. Run Photorec first to lift any problem data from the flash memory before starting the Testdisk repair procedure, since sometimes any repair attempt could theoretically make things work, so it is best to always do a recovery first.

Also another highly recommended program for most data recovery problem (USB stick use for free, hard disk use you need to buy the program) is Zero Assumption Recovery, which you can buy on a weekend with their special weekend discount for $29.95, but as said: Recovering photos from flash is free.

I have all of them in my tool kit, and they are must have for me.
 
One last piece of advice: Windows Checkdisk in error correct mode should only be run as a routine maintenance tool for very minor problems related to the file system. Do not run chckdsk if there is already a hardware or more serious data integrity problem, it can make things considerably worse and potentially unrecoverable. Always lift the data off first ( ... on a USB stick, slightly different story on a dying mechanical hard drive, but that would be another topic ...).

Hope this helps some.

Regards,

Brahman

Innuendo:
Wow, good advice. I haven't heard anything about fake USB sticks lately, but I haven't been seeking the information out. Last I checked eBay was over-run with them. A good rule of thumb is only buy reputable brand USB drives from reputable vendors.

Sounds simple enough, but for some reason common sense flies out the window when a person goes shopping online for a USB drive. They see 8, 16 or whatever GB for something ridiculous and don't think it through. If it sounds too good to be true it usually is.

What used to be the dirty little secret of the USB drive industry was how hard it was (is?) to find the read/write speeds on every drive. Sometimes two different brand drives which are otherwise identical have radically different read and write capabilities. Sometimes for just about the same price you can get a drive that's 3 times or more faster than its competitors.

And to further extend on the point of fake drives reporting fake drive space the first thing I always do is find some h-u-g-e files and copy those files to entirely fill up the new flash drive. Then I copy them back to my HD & run a compare on the original files vs. the copy that just made the trip to the flash drive and back. Test results should report the file sets as being identical or you've got a problem.

Curt:
Most interesting thread. All was new to me. Thanks for telling!
 :up:

brahman:
the first thing I always do is find some h-u-g-e files and copy those files to entirely fill up the new flash drive. Then I copy them back to my HD & run a compare on the original files vs. the copy that just made the trip to the flash drive and back. Test results should report the file sets as being identical or you've got a problem.
-Innuendo (July 04, 2009, 09:21 AM)
--- End quote ---

Yes - that is the best test procedure for new USB sticks and that is exactly what the tool h2testw from the German Heise magazine publisher (link above) does, but all on the push of a button and in one whole swoop!  :Thmbsup:

Regards,

Brahman

Innuendo:
Then I'll be keeping that tool in mind if/when I get another flash drive. Right now I have an 8GB Sandisk Contour and the only way I can see myself replacing it is if it were lost or I outgrow it.

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