In the case where an error included in data read from the nonvolatile memory device 110 is greater than or equal to a reference value (e.g., the number of error bits is greater than or equal to the reference number of error bits), the reclaim management unit 123 may move data of a memory block, which includes memory cells storing read data, or a portion of data stored therein to another memory block. For example, in the case where data including a plurality of error bits exceeds an error correction capability of the ECC circuit 122, the reclaim management unit 123 may move data of a memory block to another memory block to maintain the integrity of data. The data movement operation may be referred to as “read reclaim”.

For example, the reclaim management unit 123 of the controller 120 according to an exemplary embodiment of the inventive concept may perform the read reclaim or partial read reclaim.

FIG. 2 is a circuit diagram illustrating a memory block included in a nonvolatile memory device of FIG. 1. A memory block BLKz having a three-dimensional (3D) structure will be described with reference to FIG. 2. However, the present inventive concept is not limited thereto, and the remaining memory blocks BLK1 to BLKz-1 may have the same or similar structures as that of the memory block BLKz. Referring to FIG. 2, the memory block BLKz includes a plurality of cell strings CS11, CS12, CS21, and CS22. The cell strings CS11, CS12, CS21, and CS22 may be arranged along a row direction and a column direction to form rows and columns.