Abstract: A data storage device includes a device interface for receiving data access requests, a plurality of non-volatile memory devices and a controller that accesses the non-volatile memory devices in response to the received data access requests. The plurality of non-volatile memory devices include at least one of flash memory; compact flash memory; magnoresistive RAM; ferroelectric RAM; any type of volatile memories, such as dynamic and static RAM, maintained as non-volatile with the use of a power subsystem; mechanical memory devices and microelectromechanical memory devices.

Abstract: In general, in one aspect, the disclosure describes a data storage device that includes a device interface for receiving data access requests, more than two disk drives having platter sizes less than 3.5 inches in diameter, and a controller that accesses the disk drives in response to the received data access requests.

Abstract: In general, in one aspect, the disclosure describes a cache that includes interface that receives data access requests that specify respective data storage addresses, a back-end interface that can retrieve data identified by the data storage addresses, cache storage formed by at least two disks, and a cache manager that services at least some of the requests received at the front-end interface using data stored in the cache storage.