What is a RAID in technology?

an industrial standard which exist for multiple-disk database schemes, is termed as RAID. The basic strategy used in RAID is to replace the large capacity disk drive with multiple smaller capacity disks. there are several RAID levels. RAID 0 is for striping: Applications requiring high performance for non critical data. RAID 1 is for Mirroring : (Typical applications) System drives; critical files. ther are 6 RAID levels may be its in the form of disks overlaping one upon the another. With this background can any one give detailed, pictorial form of RAID Thank you, Suman (MCA student)