RAID History

RAID began as a research project at the University of California, Berkeley in the 1980s. At that time, the costs of disk drives were considerably higher than they are today. Mainframe and midrange disk subsystems were relatively expensive, but newer, smaller, and less expensive disk drives were starting to emerge for personal computers. The team at Berkeley perceived an opportunity to combine these newer, cheaper disk drives in ways that would allow them to be used to achieve the same reliability as mainframe and midrange disk products, but at a much lower cost. The goal of RAID has been to deliver similar or better reliability, performance, and capacity by aggregating several smaller disk drives.

Today, RAID is a staple in most storage products. It can be found in disk subsystems, host bus adapters, system motherboards, volume management software, device driver software, and virtually any processor along the I/O path. Because RAID works with storage address spaces and not necessarily storage devices, it can be used on multiple levels recursively.