US Patent 8719488 Efficient mapping of data blocks in a flash cache

A storage device made up of multiple storage media is configured such that a flash memory serves as a cache for data stored on a backend storage device having one or more magnetic storage media. The storage device includes a controller configured to maintain a direct mapping from respective backend block addresses of the backend storage device to respective physical addresses of the flash memory. Such mapping is used to translate a backend block address of the backend storage device at which a first block is stored into a physical address of the flash memory at which the first block is cached.