A solid state drive architecture with memory card modules

Solid State Drive (SSD) for the consumer market may not require extreme high performance, but it does want high density at a low cost. Redundant Array of Inexpensive (or Independent) Disks (RAID) are built up by a group of independent disk drives, not inside a disk drive. This makes a RAID system not as inexpensive as expected in the beginning and in the end the system often becomes expensive, large in size and complexity. It is not well suited for consumer applications. This paper proposes a new structure, to build up a high density SSD in a RAID system by using SD or MMC/ eMMC modules instead of independent drives. A SSD controller chip with embedded RAID (eRAID) multiple level functions was designed and applied to verify this proposal. By using this controller and eMMC modules, a redundant array of independent modules (RAIM) is built up as an inexpensive single drive and proven to work. The result revealed that a RAIM can be a single SSD drive as well as a micro-RAID system. By utilizing RAIM SSD units a more sophisticated RAID system can be constructed at lower costs and greater performance in a much smaller configuration, which is more suitable as home cloud storage, etc.