This chapter begins our look into RAID. Throughout the next three chapters, we will detail the history, functionality, protection, reliability, availability, and fault tolerance capabilities of storing data on subsystems known as "redundant arrays of independent disks."

The reliability and the availability of data are the two most important requirements of a storage system. The more bulletproof you can make any storage system, the more reliable it becomes. The availability of data, on the other hand, implies that data can be stored and recovered in the most rapid, accurate fashion, and with a minimum of outside activity or interaction. Both of these requirements are essential to good system performance, whether that data is intended for the home PC, the mainframe computer, or the mission-critical media for a client's commercial that can air only once during the Super Bowl.

Since the beginning, video media, whether stored on magnetic videotape, optical or magnetic disk...