Summary: While the technology continues to improve, the fact is that flash memory has a limited number of times it can be written to. I can, in fact, wear out.
I have a database application that I share between multiple computers. We keep the database itself on a USB thumb drive and simply move that drive to the other computers as needed. The database is never copied off the thumbdrive, we just update it in place. Seems very simple.
A friend of mine just told me that I was asking for trouble. He said something about thumbdrives "wearing out", and that sooner or later, probably sooner, the data on my thumbdrive would become corrupt.
Is that true? Do these USB drives actually wear out?
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Let me put it this way: I strongly recommend that you backup the contents of that drive - also sooner rather than later.
Flash memory, the type of memory used in USB thumb drives and other devices, is very, very cool. In fact I'm loading up a gigabyte SD-Ram card for my MP3 player as I type this. But there is a dark side that people don't talk about much.
Flash memory "wears out".
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Flash memory chips are called "flash" because in order to write to it, the memory is loaded, and then a signal is sent to the memory circuitry that says "remember this" - kind of like the flash on a camera. (In all honesty, I don't know if modern flash memory uses this exact technique, but it remains a fairly accurate metaphor for the process.)
Once the memory has been "flashed", power can be completely removed and the memory will retain whatever was written to it.
The "problem" is that memory can be flashed only so many times. I'm finding numbers between 10,000 and 100,000 times - though as with anything, I'm sure that is increasing over time as well. Regardless, there is a limit. When that limit is approached, some portion of the memory may not properly remember what was written to it, resulting in corruption. It may only take a single bit of information to be wrong, or to "wear out", for the entire contents of a flash memory chip to be lost.
Scary, huh?
Some flash memory chips, perhaps even most, now also include circuitry to avoid "bad bits". Meaning that if portion of the flash memory finally wears out and goes bad, the chip itself can compensate and look like everything is fine. But that only lasts so long ... it doesn't prevent failure, it only postpones it.
Now, in your case, you're using USB thumbdrive in perhaps the worst possible way for longevity. Database applications in particular are notorious for writing to the disk - a lot - as tables, fields, indexes and the like are updated. Even if you don't write to your database, the files may be updated with things like "last access" information and other administrivia that still results in the USB drive being written to.
With all that writing going on, suddenly 10,000 or 100,000 writes to the same location in the flash memory doesn't seem that far fetched. Remember, in the unluckiest case, it might only take one worn-out bit of information to render the entire contents unreadable.
The best use of USB thumb drives and other flash memory based devices is simply copy-to and copy-from. By that I mean copy the information to the thumbdrive to store it, copy it from the thumbdrive to a local hard disk to use it, and then copy it back to the thumb drive to store it. Never run disk-intensive applications directly against files stored on the thumb drive. If you copy to and from even 10 times a day, that's still close to three years of usage for the low end of the flash memory lifespan. (Yes, I know that's not exact. In fact, it's way more complex than that, factoring in things like the type of file system, FAT or NTFS, the efficiency of the device driver, and even the circuitry on the specific flash memory device - but it's a good order of magnitude.)
You may also note that your application speeds up when you copy your database to the hard disk for use. While reading flash memory is typically quite fast, writing is not.
And finally, if you really need external storage, a thumbdrive may simply be the wrong solution to your problem. There are plenty of external hard drives that could do the same job without the write limitations. Or perhaps a networked solution is the way to go.
Related:
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Ask Leo! - How can I tell if I have USB 2.0?
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Ask Leo! - Can I use a USB RAM stick to increase system memory?
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Imation - USB Flash Drives - You CAN Take It with You - includes the write limit information referenced above.
Article C2618 - April 12, 2006
I use USB drives pretty regularly with some pen drive apps, especially T-bird and Firefox and a few recovery tools I use to fix peoples computers like Bart-PE, Ubuntu and file recovery stuff. I haven't had any problems but I keep a folder on my hard drive for each USB drive and back up regularly. No hardware is immune to failure. My only loss would be the $10 I invested in my stick.
Here's an old classic:
Yesterday-The Backup Song
Yesterday,
All those backups seemed a waste of pay.
Now my database has gone away.
Oh I believe in yesterday.
Suddenly,
There’s not half the files there used to be,
And there’s a milestone hanging over me
The system crashed so suddenly.
I pushed something wrong
What it was I could not say.
Now all my data’s gone
and I long for yesterday-ay-ay-ay.
Yesterday,
Posted by: Mark at April 16, 2009 5:51 AMThe need for back-ups seemed so far away.
I knew my data was all here to stay,
Now I believe in yesterday
I've only had my 8gb kingston thumb drive for a short while and havent used it for much, the occasional word document or so. But as if overnight, I don't know what happened, but now my thumb drive has been reduced to the capacity of 4mb! and also says that it needs to be formatted. I used some partition making program provided by kingston so i don;t know if that screwed up the thing or maybe its somehow this 'wearing out' phenomenon. I've formatted it but it still remains on 4mb capacity! What could have happened?? I don't recall doing any thumb drive no-nos recently...
05-May-2009
They have error protection and will attempt to block out bad blocks and work around the problem.
Posted by: Jint at September 24, 2009 4:33 PMWikipedia has a way of getting people to believe stupid things (Like flash drives will suddenly stop working after 3 years). And people have a way of believing everything posted on Wikipedia to be verbatim… and then, by spreading the lie, it comes to the point where no one realizes that it was some Wiki-Dolt who misinterpreted how flash-memory works that made the error in the first place.
First off, those numbers are made up. A press release may use single digit numbers; but for everyone else, tolerances are far more accurate. 100k with a tolerance of 10k would portray a person who "knows what s/he's talking about." The 10k is worse, showing a 90% decrease from the first estimate? Clearly whoever feed you this information did not know what s/he was talking about.
Are you old enough to remember when we said that humans had 100,000 genes? Then we had people saying “okay, we made that information up, there are only 20k genes” and now that same number is climbing again as human superiority must be portrayed in all manners (including the number of genes).
Now people see the words “flash memory” and assume that it has this fixed flaw (or, at the very least, that it cannot exceed 100k). But such an accusation is the same as claiming that Digital Cameras can create compression artifacts and as such Film-Based Cameras also create said artifacts. Flash memory describes a type of memory, but there are many forms of memory under that name.
The worse aspect of this whole mess is how ‘fixed’ this number is. Look at it as buying a new car, you have no guarantee when or if problems will occur, people may throw "averages" at you, but those statistics may only pertain to the factory in Tulsan. And unlike a car, your your FILESYSTEM has the ability to ignore the problems.
That's right, all this jabber about how long your flashdrive will last? Bupkis. You can get write errors, but those are handled by your OS (and those sectors marked as 'bad sectors') but will the data auto-corrupt after 3 years? Hell no. But that's what the Wiki-Dolts want people to think… and that is what they have.
I hold here a 5 year old flash drive, "clean formatted" 8 times (writes 0 in every bit, better than defrag), information copied back and forth like crazy… and it still works.
Posted by: Misinformation, the Product of Wikipedia at January 14, 2010 4:05 PMTo remove a "Fash Drive" from my computer, what do I have to close?
Thank you in advance.
Posted by: Arthur R. Leger at February 4, 2010 8:59 AMArthur