MEMORY DEVICE AND OPERATING METHOD THEREOF

The present disclosure relates to a storage device that can ensure that data to be written is requested from a host. The storage device includes: a buffer memory for storing data requested to be written from a host; a memory device including a plurality of user blocks, a plurality of reservation blocks for replacing the plurality of user blocks, and a plurality of power-off protection blocks for storing the buffer data stored in the buffer memory when a sudden power-off of an abnormal power interruption occurs; and a memory controller that, in response to a write operation error of the plurality of user blocks and the plurality of reserved blocks, determines whether any memory block capable of storing data requested to be written exists among the plurality of user blocks and the plurality of reserved blocks, and, according to whether any memory block capable of storing data requested to be written exists, performs write operation on the plurality of user blocks and the plurality of reserved blocks. One or mor