There is a bona fide new tier within the disk storage infrastructure that you will be hearing a lot about over the next several years: MAID. Standing for "Massive Array of Idle Disks," MAID technologies utilize a range of advanced techniques to achieve the reliability and performance of a disk environment with the economics and density comparable to a tape environment. In essence, by managing how and when disks are spun up for I/O-rather than spinning all disks all the time-MAID technologies create an entirely new level of sub-system efficiency that truly constitutes its own class of storage. This "MAID Tier" is today focused on secondary storage applications, such as disk-based backup and archival data. The intelligence behind the solutions in the enterprise MAID category is non-trivial, and we see these vendors making significant headway in the market. Chief among these players is COPAN Systems, and its Revolution 200 series of products. By applying their own proprietary advances to the MAID approach, COPAN Systems has created a platform that is uniquely applicable to both the disk-based backup and disk archival markets.