Flash Drive Media Explained
In the early days of data storage devices items such as flash drives and SD cards were an expensive luxury. Today they are common place and affordable. The drop in cost and storage capacity has made them one of the most popular mediums available to the consumer market. Today we can find them in even the most low end cell phones and cameras.
In fact, they are quickly replacing older hard disk drive technology as the go to choice. Flash media is quick and relatively reliable. However, the technology is not without its faults. One major concern with flash drives and memory cards has to do with their deterioration over time. In part, due to the way these device store our data.
NAND and NOR-Flash Drive Attributes
The advances that manufactures like to highlight with reference to flash media advancement concern NAND and NOR innovation. The differences being that NOR can be accessed directly from an address bus (random access) and thus can be used to run code. Whereas, NAND composes information at a piece level and permits page access. In other words, NOR offers random access while NAND is accessed sequentially. (see bottom notes for further explanation) While NAND may be slightly more manageable, NOR can offer better endurance. Currently, NAND tends to lead the consumer market due to its relatively cheaper manufacturing cost.
Endurance and Longevity of Your Flash Drive
When discussing endurance we are referring to the number of project delete cycles or P/E cycles, that flash media performs before deterioration begins. Deterioration is the result of oxidation which causes the flash drive to become less stable resulting in a loss of data. Early signs of this degradation are loss of speed and dependability. Errors such as failure to read will occur more frequently.
Getting the most from your Flash Drive
There are steps we can take to ensure the best performance and longevity of our storage devices. For example, the way in which we use our media has a dramatic influence. Continuous moving of large files greatly reduces the longevity and reliability of the device. It is therefore recommended one avoid unnecessary write and re-writing of information to the device. The current shelf-life one can expect for NAND flash media is a generous 100,000 P/E cycles. However a flash drive or camera memory can quickly be utilized with heavy or careless use.
Flash drive technology is cheap, easy to use and convenient. However failure, due to misuse or inevitable deterioration over time, makes our data vulnerable to loss and corruption. Consistent back-up practices are always your safest bet against critical data loss.
Random-access files enable one to read or write information anywhere on a file and access data at random. This type of direct access differs from sequential access whereby one must go from point A to point Z by passing through all the intervening points. With random access one can jump directly to point Z. A cassette tape or a VHS represent sequential access media.