Dan´s Data has posted up a review on IDE RAID. Here a snippet:

RAID stands for Redundant Array of Independent (or Inexpensive) Disks. It lets multiple drives behave like one, bigger, faster drive, by spreading data between them.

If RAID´s implemented in hardware, there´s a controller that handles the job of making multiple drives look like one. If it´s implemented in software, a special device driver does the work. Software RAID´s slower, but you don´t need the special controller. You can do it with "industrial strength" operating systems like Windows NT and Linux.

The two elementary kinds of RAID are called "striping" and "mirroring". In striping, a.k.a. "RAID Level 0", you use more than one drive, and the data´s sent to or read from each of them in turn. Byte one to drive one, byte two to drive two, and so on until you run out of drives and go back to the first one again.

Striping improves performance - you add together the transfer rates of the two drives, provided your drive interface has the bandwidth to handle it. But it doesn´t provide any redundancy at all. If one drive in a "stripe set" fails, the whole set´s hosed. So you shouldn´t use it for important data. Well, not without mirroring as well, anyway.

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