(n.) An integrated collection of similar hard disk drives that function together to provide greater speed and integrity of data than a single drive. Originally, the I stood for inexpensive, referring to the 3.5-inch and 5.25-inch disks used for the first RAID systems. Drives are striped so that the writing of data may be synchronized between disks, and parity refers to the bits used for error correction. The following standard RAID specifications exist:
- RAID 0 Nonredundant striped array
- RAID 1 Mirrored arrays
- RAID 2 Parallel array with error correction code (ECC)
- RAID 3 Parallel array with parity
- RAID 4 Striped array with parity
- RAID 5 Striped array with rotating parity