Despite their differences, flash memory and hard disks have something in common: they are both what is known as non-volatile memory. Non-volatile memory, unlike volatile memory, retains its data even when not receiving electrical power. This allows flash memory and magnetic hard disks to be used for long-term computer storage. With flash memory gaining in popularity, the comparison between hard disks and flash memory, called a solid-state disk when used to replace a hard disk, becomes more important as time goes on.
How Hard Disks Work
Hard disks (or hard disk drives) are complicated works of modern mechanics. A motor turns the magnetic disks, sometimes called "platters," while arms scan the spinning disks. Data is stored in the form of magnetic charge--either a one or a zero--and arranged into sectors on each disk of the hard drive. The arms read and write data to the hard drive.
How Flash Memory Works
Flash memory is also a complicated technology, but it involves little mechanical ingenuity. In flash memory, data is also effectively stored in the form of ones and zeros. A zero is created by an empty cell, a one by a cell where an electrical charge is trapped.
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The name "hard disk drive" is derived from the hard disks that make up the drive. The name "flash" refers to the fact that memory can be erased quickly and in large chunks, something flash memory's predecessors were not capable of doing. The name "solid-state drive" is derived from the fact that none of the drive's parts move, unlike mechanical hard disks.
Hard drives are still the most common type of non-volatile storage used in computers. The technology is far more developed than the younger flash memory and much larger storage capacities are available in hard drives than in the newer flash memory-powered, solid-state drives. While performance gains remain low and prices remain high, most computer users will find little reason to use a solid-state drive in lieu of a hard drive.
Using Flash Memory
Certain computer users may benefit from using a flash memory solid-state drive more than others. Factory and construction work, where workplace trauma may damage computer data, calls for a more rugged computer and storage with less chance of being damaged. Flash memory solid-state drives lead the way in this field because their lack of moving parts means there are fewer ways data can be lost.