Flakey 8GB Flash Drive

probably a fake. Probably has a smaller chip than advertised. Fill it up, eject it, reinsert and try to read all the files back. Files verify after copy because the OS is caching the file and giving you back the cache instead of what's actually on the drive. Eject/reinsert causes a re-read of the actual drive.

An unfortunately high percentage of "high-capacity" no-name flash drives are bogus. They actually have smaller storage capacities, and their controller chips have been deliberately programmed to report a false capacity. Accesses to sectors falling beyond the device's actual storage boundary will often "wrap around" in an unpredictable fashion, overwriting existing sectors with new data. The result is just as you have observed - corrupted files.

This sort of falsification is often not detected by an operating system's normal formatting routine, since formatting doesn't require writing to more than a very small fraction of the sectors in the filesystem.

In order to detect such forgeries in a definitive way, it's necessary to write a unique pattern to each individual sector (e.g. fill each sector with its own sector number), then read back every sector and see if it has the right unique pattern in it. An honest drive will past this test; a dishonest one will fail, and you'll be able to see which sector's data clobbered which other sector.

From the behavior you report, it sounds as if you may have a 1-gig drive, relabelled and reprogrammed to appear as if it were an 8-gig drive.

Such counterfeit drives are not uncommon on eBay and similar online auction sites, at electronic flea-markets, and so forth. It's best to buy high-capacity drives from reliable local sources, and then test the drives to confirm their legitimacy - and if they fail, take 'em back to the store and raise a stink.

Remember, "cheap" is often very expensive.

Fortunately, only a $15 experiment. Any clever way to get 1GB to work reliably or it is just toast?

Thank you both for the good clues.

Can you just make a 1GB FAT32 or NTFS partition on it?

This kind of fraud is pretty typical of cheap Chinese products. If the deal is too good to be true it usually is not true! I was reminded of this recently when buying a nice-looking no-name universal remote control for $2.00 at a local dollar emporium. After struggling to get the thing working I opened it up and found a flimsy blank circuit board with just a few components designed to make an LED blink when you touch a button -- the whole thing was a fake, and was probably meant to sell at a higher price.

I believe I need to reprogram the controller chip [MXT6208A]. I see the software utility to accomplish this for another species of controller. Google finds a possible tool for this chip also but the site is in Chinese and I'll need help from a Chinese friend to get further with that experiment. All for

are

Just wondering - are you perhaps using it with a USB hub? I've had problems in the past with larger capacity sticks in hubs. Particularly hubs that include a jack for external power and that I tried to power from my PC's jack instead. The addition of external power seemed to cure my problems.

On the other hand, I recently bought a PNY 8GB flash drive that I couldn't get to behave correctly, no matter what. I e-mailed them and they just sent me another one (that worked, for free.)

My sister bought a universal remote control for just about that price, and it worked...

You know, with today's technology, it really wouldn't cost much more to build a real functional remote than to make a fake one that blinked an LED. Microcontrollers are under a buck and most are far more powerful than needed for that application.

Why don't you just toss it and buy a new one?

-- The Lady from Philadelphia