RAID
You may have seen the computer hard drive term “RAID” and wondered what it meant or whether it was something you might want. RAID is an acronym that refers to a setup using multiple disks to make information processing faster and/or safer. A common explanation of the meaning of the term is “Redundant Array of Inexpensive Disks”. The term “Inexpensive” is misleading, however, and others use “Independent” or “Interconnected”. All of this straining to find a word beginning with the letter “I” is irrelevant so take your pick. Everybody just uses RAID.
Multiple disks can be used together in various ways, depending on your purpose. I have previously discussed some of these disk setups elsewhere but RAID is becoming more common on high-end home computers so I am visiting the topic again.
If protecting data against drive failure is paramount, a method called “mirroring” is used. This means that data is copied on more than one drive so that the failure of one drive still leaves the data intact on another drive. It also allows for faster reading of information. Obviously, this setup costs you twice as much for the same storage capacity but it is one way to not have to worry about backing up. (Important data should still be backed up to an external medium, however.) In the jargon of the trade, the basic mirroring setup is called RAID-1. There are also more complicated setups using three or more disks but these are expensive and are used only in servers and where maximum fault tolerance is essential.
Gamers and others who put a premium on systems being fast may use another RAID setup that uses “striping”. In this method, information is stored by allocating it alternately and evenly to each of the disks. The purpose is to speed up getting the information on and off. The basic setup is called RAID-0. You get to use the full capacity of both disks. If one of the drives fails, however, everything is lost since various pieces of a file are stored on different disks. In order to provide fault tolerance, more complicated setups can be also made.
More detail on RAID can be found in a TechRepublic article by George Ou (registration required).