NAND (Not And) hard drives are very fast, high-capacity, solid-state flash memory drives. Predicted to become the drive of choice in laptops, NAND hard drives have many significant advantages over other types of flash memory. NAND refers to the architecture of the chip, differing it from NOR (Not Or) flash memory. NOR flash memory is commonly used in cell phones, PDAs and other devices in which small programs are executed in place rather than written to RAM. NOR flash memory is a good choice for applications that require little memory and do most of their work on unchanging code, such as boot directions or operating systems.
For changing data, however, NAND hard drives are superior to NOR flash memory. NAND is more cost effective and the chips are smaller, allowing more memory to be packed into the same size space. These hard drives also erase faster than NOR flash memory. This allows NAND to write faster, as flash memory must erase memory blocks before writing to them. Furthermore, NAND features a longer lifespan of more erase cycles. These factors combine to make this type of flash memory a logical choice for high-capacity storage and manipulation of changing data.
NAND hard drives also have significant advantages over traditional hard drives. Solid-state means that the drives do not have moving parts that can break down. They are also much faster than traditional drives and, like USB flash drives, they are completely silent. As if these favorable attributes weren't enough, NAND drives use very little power. This is particularly important to laptop users.
However, as of Spring 2006, traditional hard drives are so inexpensive that it's difficult for newer technology to compete in the commercial marketplace. Costs for a large NAND drive are still prohibitive. Industry insiders predict affordable solid-state laptops running NAND hard drives by 2009. Exact timing is dependent on manufacturing costs, which continue to fall. Also, with all of the advantages of these drives, consumers will likely be willing to dig into their wallets.
