In particular, the flash memory device is widely used in various electronic products as a mass storage device. Even though the flash memory device is a nonvolatile memory device, data stored in the flash memory device may be lost due to various factors, such as a temperature, read or program disturbance, and charge loss.

According to an exemplary embodiment of the present inventive concept, a storage device is provided as follows. A nonvolatile memory device includes a plurality of memory blocks. Each of the plurality of memory blocks is divided into a plurality of zones and is formed on a substrate. Each of the plurality of zones comprises one or more word lines. A controller performs a reliability verification read operation on a first zone of the plurality of zones of a memory block selected from the plurality of memory blocks if a number of read operations performed on the first zone reaches a first threshold value and performs the reliability verification read operation on a second zone of the plurality of zones of the selected memory block if a number of read operations performed on the second zone reaches a second threshold value.

According to an exemplary embodiment of the present inventive concept, a storage device is provided as follows. A nonvolatile memory device includes a plurality of memory block zones each of which includes one or more memory blocks. A controller performs a reliability verification read operation on a memory block zone among the plurality of memory block zones if a number of read operations performed on the memory block zone reaches a threshold value and perform a read reclaim operation on the memory block zone based on a number of error bits detected through the reliability verification read operation.