NAND flash memory is a type of non-volatile storage technology that does not require power to retain data. An important goal of NAND flash development has been to reduce the cost per bit and increase maximum chip capacity so that flash memory can compete with magnetic storage devices like hard disks. NAND flash has found a market in devices to which large files are frequently uploaded and replaced. MP3 players, digital cameras and USB drives use NAND flash. NAND has a finite number of write cycles. NAND failure is usually gradual as individual cells fail and overall performance degrades, a concept known as wear-out. To help compensate, some vendors overprovision their systems by including more memory than is actually claimed. When a NAND card wears out, the user simply buys a new one, and the device continues to function. By passing the expense of additional storage on to the consumer, manufacturers have been able to lower the price of consumer electronic devices significantly. New developments in NAND flash memory technology are making the chips smaller, increasing the maximum read-write cycles and lowering voltage demands