A storage device includes a nonvolatile memory device and a controller configured to send first data, an address, and a first command to the nonvolatile memory device. The controller also sends at least one data to the nonvolatile memory device after sending the first command. The nonvolatile memory device is configured to initiate a program operation, which is based on the first data, in response to the first command. When receiving the at least one data from the controller, the nonvolatile memory device is configured to continue to perform the program operation based on the first data and the at least one data.