Patent ID: 8489855

Claim:
A solid state drive adapted for use with a host system, the solid state drive comprising: a controller; and at least one NAND flash-based non-volatile memory device comprising pages that are organized into memory blocks, the memory blocks being minimum-erasable units of the memory device, the pages being sequentially programmable and readable such that some of the memory blocks are partially written blocks, the memory blocks being partitioned into at least first and second pools that constitute two virtual address spaces of the memory device, the first pool being a user-accessible pool to which the controller virtually assigns a plurality of the memory blocks as user-accessible memory blocks, and the second pool being an over-provisioning pool to which the controller virtually assigns a plurality of the memory blocks as over-provisioned memory blocks; wherein the solid state drive is adapted to operate such that each of the memory blocks can be transitioned between the user-accessible pool and the over-provisioning pool, data are written to pages of the memory blocks virtually assigned to either the user-accessible pool or the over-provisioning pool, pages from a first partially written block are copied into a second partially written block without accessing the host system, and the first partially written block is erased to constitute an erased block after all pages of the first partially written block have been copied to the second partially written block and without a TRIM or erase command from the host system.