A storage device includes a
volatile memory and a storage controller, which is configured to control the
volatile memory. The
volatile memory includes a
memory cell array, which has a plurality of sub-
cell arrays therein, and a plurality of sub-wordline driver blocks, which are configured to drive sub-wordlines electrically connected to at least one of the plurality of sub-
cell arrays. The storage controller includes: a volatile
memory interface configured to transmit data to and receive data from the volatile memory, and detect an error bit(s) of data output from the volatile memory, a
working memory configured to store a structure map table, which maps unit areas of the volatile memory, the sub-wordlines, and the plurality of sub-wordline driver blocks, and a processor, which is configured to: update an error count of a unit area of the volatile memory that corresponds to the error bit(s) detected from the volatile
memory interface to the structure map table, detect at least one of a defective sub-wordline and defective sub-wordline driver block, by accessing the structure map table, and then repair at least one
memory cell connected to the defective sub-wordline and / or repair at least one
memory cell associated with the defective sub-wordline driver block.