Todd Walton wrote:
On Fri, 11 Feb 2005 09:16:59 -0800, [EMAIL PROTECTED]
<[EMAIL PROTECTED]> wrote:
Can I expect USB thumb drives to last 5-10 years like good ol' PC
hard drives or should I always expect USB thumb drives to be
this flaky?
The expected life of a USB storage device depends upon the memory used in it. Cheaper
flash memory has a lifetime of 100,000 writes. Better devices have a life of 1,000,000.
In addition, these devices have "sectors" in them - a block of memory whose
size depends upon the total size of the chip used and the mfg. The devices write cycles
are based upon the number of times a given sector is written. So, if the same sector is
written over and over, while other sectors are not, it will wear out before the others.
(e.g. - re-writing the same file many times will re-write the same sector many times as
well). Essentially, like a HDD, these things will develop bad blocks. Whether the entire
device is considered bad when a block goes bad, or just that particular block would be
determined by the software.
These devices may also be susceptible to ESD (key word *may*). With
electronics, you generally get what you pay for. Cheap (or no) ESD protection
is a great way to lower the cost of a product, but it will also lower the
reliability. Dirt is a factor, moisture, basically all the things that can, and
do, effect memory and other electronic devices.
So, how long will they last? That depends upon how they are treated, how often
you use them, and the quality of the components. For these reasons I never put
mine on my key chain and instead leave it in my laptop bag with the connector
cover on it. I also bought an $80 256MB device - one of the more expensive ones
available (at Fry's) at the time. How long will mine last? Who knows, but I
don't expect it to last for years (I've had it for ~1 yr. now).
PGA
--
Paul G. Allen
Owner, Sr. Engineer, Security Specialist
Random Logic/Dream Park
www.randomlogic.com
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