If USB sticks and/or external drives have limits, I mean on the number of writes and deletes, how about reads and copys?
Are number of reads and/or copys also have limits in USB sticks or external drives?
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Yes flash drives have limited writes – Ramhound Aug 8 '13 at 19:44
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2Think of it as a piece of paper where you can write and erase and write again. Erasing slowly wears away the paper until it gets holes, but reading causes essentially no wear. – Daniel R Hicks Aug 8 '13 at 21:24
I believe the limits you're referring to are the limited number of erase operations that a NAND Flash (the type of memory most commonly used in SSDs) cell can sustain before it ceases to work. Each erase operation causes a small amount of damage to the cell, and eventually the cell will stop working.
What this means is that any operation that results in data being erased from the drive will cause wear. Deleting a file generally won't cause it to be immediately erased from the SSD; because, as Taylor says, the cells storing that file are simply marked as no longer in use. If a new file needs to be written to those cells, they must first be erased, and that is what causes wear to the drive. That's why in general people say that flash memory has a limited number of writes.
Reads on the other hand do not require erasing, and so do not contribute to this "write limit."
Having said all that, note that modern flash memory's write limits are so high that you're extremely unlikely to reach them before your SSD/flash drive is outdated for other reasons. For example, this article concludes that writing 80M bytes / sec to a typical (in 2007) SSD would yield an endurance life of 51 years.
